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	<id>https://drorbn.net/index.php?action=history&amp;feed=atom&amp;title=1617-257%2FHomework_Assignment_18</id>
	<title>1617-257/Homework Assignment 18 - Revision history</title>
	<link rel="self" type="application/atom+xml" href="https://drorbn.net/index.php?action=history&amp;feed=atom&amp;title=1617-257%2FHomework_Assignment_18"/>
	<link rel="alternate" type="text/html" href="https://drorbn.net/index.php?title=1617-257/Homework_Assignment_18&amp;action=history"/>
	<updated>2026-05-05T13:12:38Z</updated>
	<subtitle>Revision history for this page on the wiki</subtitle>
	<generator>MediaWiki 1.39.6</generator>
	<entry>
		<id>https://drorbn.net/index.php?title=1617-257/Homework_Assignment_18&amp;diff=16423&amp;oldid=prev</id>
		<title>Drorbn: /* Doing */</title>
		<link rel="alternate" type="text/html" href="https://drorbn.net/index.php?title=1617-257/Homework_Assignment_18&amp;diff=16423&amp;oldid=prev"/>
		<updated>2017-04-20T14:41:57Z</updated>

		<summary type="html">&lt;p&gt;&lt;span dir=&quot;auto&quot;&gt;&lt;span class=&quot;autocomment&quot;&gt;Doing&lt;/span&gt;&lt;/span&gt;&lt;/p&gt;
&lt;table style=&quot;background-color: #fff; color: #202122;&quot; data-mw=&quot;interface&quot;&gt;
				&lt;col class=&quot;diff-marker&quot; /&gt;
				&lt;col class=&quot;diff-content&quot; /&gt;
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				&lt;col class=&quot;diff-content&quot; /&gt;
				&lt;tr class=&quot;diff-title&quot; lang=&quot;en&quot;&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: #fff; color: #202122; text-align: center;&quot;&gt;← Older revision&lt;/td&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: #fff; color: #202122; text-align: center;&quot;&gt;Revision as of 10:41, 20 April 2017&lt;/td&gt;
				&lt;/tr&gt;&lt;tr&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 20:&lt;/td&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 20:&lt;/td&gt;
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&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;/ol&amp;gt;&lt;/div&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;/ol&amp;gt;&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;br /&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;br /&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot; data-marker=&quot;−&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;u&amp;gt;&#039;&#039;&#039;Problem C&#039;&#039;&#039;.&amp;lt;/u&amp;gt; Let &amp;lt;math&amp;gt;\omega=ydx\in\Omega^1({\mathbb R}^2_{x,y})&amp;lt;/math&amp;gt;.&lt;/div&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot; data-marker=&quot;+&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;u&amp;gt;&#039;&#039;&#039;Problem C&#039;&#039;&#039;.&amp;lt;/u&amp;gt; Let &amp;lt;math&amp;gt;\omega=&lt;ins style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;-&lt;/ins&gt;ydx\in\Omega^1({\mathbb R}^2_{x,y})&amp;lt;/math&amp;gt;.&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;ol&amp;gt;&lt;/div&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;ol&amp;gt;&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;li&amp;gt; Let &amp;lt;math&amp;gt;\Gamma&amp;lt;/math&amp;gt; be the graph in &amp;lt;math&amp;gt;{\mathbb R}^2_{x,y}&amp;lt;/math&amp;gt; of some smooth function &amp;lt;math&amp;gt;f\colon[a,b]\to{\mathbb R}&amp;lt;/math&amp;gt;. Using the inclusion of &amp;lt;math&amp;gt;\Gamma&amp;lt;/math&amp;gt; to &amp;lt;math&amp;gt;{\mathbb R}^2_{x,y}&amp;lt;/math&amp;gt;, consider &amp;lt;math&amp;gt;\omega&amp;lt;/math&amp;gt; also as a 1-form on &amp;lt;math&amp;gt;\Gamma&amp;lt;/math&amp;gt;. What is &amp;lt;math&amp;gt;\int_\Gamma\omega&amp;lt;/math&amp;gt;?&lt;/div&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;li&amp;gt; Let &amp;lt;math&amp;gt;\Gamma&amp;lt;/math&amp;gt; be the graph in &amp;lt;math&amp;gt;{\mathbb R}^2_{x,y}&amp;lt;/math&amp;gt; of some smooth function &amp;lt;math&amp;gt;f\colon[a,b]\to{\mathbb R}&amp;lt;/math&amp;gt;. Using the inclusion of &amp;lt;math&amp;gt;\Gamma&amp;lt;/math&amp;gt; to &amp;lt;math&amp;gt;{\mathbb R}^2_{x,y}&amp;lt;/math&amp;gt;, consider &amp;lt;math&amp;gt;\omega&amp;lt;/math&amp;gt; also as a 1-form on &amp;lt;math&amp;gt;\Gamma&amp;lt;/math&amp;gt;. What is &amp;lt;math&amp;gt;\int_\Gamma\omega&amp;lt;/math&amp;gt;?&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;/table&gt;</summary>
		<author><name>Drorbn</name></author>
	</entry>
	<entry>
		<id>https://drorbn.net/index.php?title=1617-257/Homework_Assignment_18&amp;diff=16286&amp;oldid=prev</id>
		<title>Drorbn: /* Doing */</title>
		<link rel="alternate" type="text/html" href="https://drorbn.net/index.php?title=1617-257/Homework_Assignment_18&amp;diff=16286&amp;oldid=prev"/>
		<updated>2017-03-28T16:32:36Z</updated>

		<summary type="html">&lt;p&gt;&lt;span dir=&quot;auto&quot;&gt;&lt;span class=&quot;autocomment&quot;&gt;Doing&lt;/span&gt;&lt;/span&gt;&lt;/p&gt;
&lt;table style=&quot;background-color: #fff; color: #202122;&quot; data-mw=&quot;interface&quot;&gt;
				&lt;col class=&quot;diff-marker&quot; /&gt;
				&lt;col class=&quot;diff-content&quot; /&gt;
				&lt;col class=&quot;diff-marker&quot; /&gt;
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				&lt;tr class=&quot;diff-title&quot; lang=&quot;en&quot;&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: #fff; color: #202122; text-align: center;&quot;&gt;← Older revision&lt;/td&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: #fff; color: #202122; text-align: center;&quot;&gt;Revision as of 12:32, 28 March 2017&lt;/td&gt;
				&lt;/tr&gt;&lt;tr&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 6:&lt;/td&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 6:&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;Ponder the questions in sections 34 and 35, yet solve and submit only the following problems:&lt;/div&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;Ponder the questions in sections 34 and 35, yet solve and submit only the following problems:&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;br /&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;br /&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot; data-marker=&quot;−&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;u&amp;gt;&#039;&#039;&#039;Problem A.&#039;&#039;&#039;&amp;lt;/u&amp;gt; Consider &amp;lt;math&amp;gt;S^{n-1}&amp;lt;/math&amp;gt; at the boundary of &amp;lt;math&amp;gt;D^n\subset{\mathbb R}^n&amp;lt;/math&amp;gt;, taken with its standard orientation, and let &amp;lt;math&amp;gt;\iota\colon S^{n-1}\to{\mathbb R}^n&amp;lt;/math&amp;gt; be the inclusion map. Let &amp;lt;math&amp;gt;\omega=\iota^\ast\left(\sum_i(-1)^&lt;del style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;ix_idx_1&lt;/del&gt;\wedge\dots\wedge\widehat{dx_i}\wedge\dots\wedge dx_n\right)\in\Omega^{\text{top}}(S^{n-1})&amp;lt;/math&amp;gt;. Prove that if &amp;lt;math&amp;gt;(v_1,\ldots,v_{n-1})&amp;lt;/math&amp;gt; is a positively oriented basis of &amp;lt;math&amp;gt;T_xS^{n-1}&amp;lt;/math&amp;gt; for some &amp;lt;math&amp;gt;x\in S^{n-1}&amp;lt;/math&amp;gt;, then &amp;lt;math&amp;gt;\omega(v_1,\ldots,v_{n-1})&amp;lt;/math&amp;gt; is the volume of the &amp;lt;math&amp;gt;(n-1)&amp;lt;/math&amp;gt;-dimensional parallelepiped spanned by &amp;lt;math&amp;gt;v_1,\ldots,v_{n-1}&amp;lt;/math&amp;gt;, and hence for any smooth function &amp;lt;math&amp;gt;f&amp;lt;/math&amp;gt; on &amp;lt;math&amp;gt;S^{n-1}&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;\int_{S^{n-1}}f\omega = \int_{S^{n-1}}fdV&amp;lt;/math&amp;gt;, where the latter integral is integration relative to the volume, as defined a long time ago.&lt;/div&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot; data-marker=&quot;+&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;u&amp;gt;&#039;&#039;&#039;Problem A.&#039;&#039;&#039;&amp;lt;/u&amp;gt; Consider &amp;lt;math&amp;gt;S^{n-1}&amp;lt;/math&amp;gt; at the boundary of &amp;lt;math&amp;gt;D^n\subset{\mathbb R}^n&amp;lt;/math&amp;gt;, taken with its standard orientation, and let &amp;lt;math&amp;gt;\iota\colon S^{n-1}\to{\mathbb R}^n&amp;lt;/math&amp;gt; be the inclusion map. Let &amp;lt;math&amp;gt;\omega=\iota^\ast\left(\sum_i(-1)^&lt;ins style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;{i-1}x_idx_1&lt;/ins&gt;\wedge\dots\wedge\widehat{dx_i}\wedge\dots\wedge dx_n\right)\in\Omega^{\text{top}}(S^{n-1})&amp;lt;/math&amp;gt;. Prove that if &amp;lt;math&amp;gt;(v_1,\ldots,v_{n-1})&amp;lt;/math&amp;gt; is a positively oriented basis of &amp;lt;math&amp;gt;T_xS^{n-1}&amp;lt;/math&amp;gt; for some &amp;lt;math&amp;gt;x\in S^{n-1}&amp;lt;/math&amp;gt;, then &amp;lt;math&amp;gt;\omega(v_1,\ldots,v_{n-1})&amp;lt;/math&amp;gt; is the volume of the &amp;lt;math&amp;gt;(n-1)&amp;lt;/math&amp;gt;-dimensional parallelepiped spanned by &amp;lt;math&amp;gt;v_1,\ldots,v_{n-1}&amp;lt;/math&amp;gt;, and hence for any smooth function &amp;lt;math&amp;gt;f&amp;lt;/math&amp;gt; on &amp;lt;math&amp;gt;S^{n-1}&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;\int_{S^{n-1}}f\omega = \int_{S^{n-1}}fdV&amp;lt;/math&amp;gt;, where the latter integral is integration relative to the volume, as defined a long time ago.&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;br /&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;br /&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&#039;&#039;&#039;Note.&#039;&#039;&#039; Earlier I made a sign mistake in the definition of and wrote &amp;lt;math&amp;gt;\omega=\iota^\ast\left(\sum_ix_idx_1\wedge\dots\wedge\widehat{dx_i}\wedge\dots\wedge dx_n\right)\in\Omega^{\text{top}}(S^{n-1})&amp;lt;/math&amp;gt;. I&#039;d like to thank the students who emailed me the correction.&lt;/div&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&#039;&#039;&#039;Note.&#039;&#039;&#039; Earlier I made a sign mistake in the definition of and wrote &amp;lt;math&amp;gt;\omega=\iota^\ast\left(\sum_ix_idx_1\wedge\dots\wedge\widehat{dx_i}\wedge\dots\wedge dx_n\right)\in\Omega^{\text{top}}(S^{n-1})&amp;lt;/math&amp;gt;. I&#039;d like to thank the students who emailed me the correction.&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;/table&gt;</summary>
		<author><name>Drorbn</name></author>
	</entry>
	<entry>
		<id>https://drorbn.net/index.php?title=1617-257/Homework_Assignment_18&amp;diff=16284&amp;oldid=prev</id>
		<title>Drorbn: /* Doing */</title>
		<link rel="alternate" type="text/html" href="https://drorbn.net/index.php?title=1617-257/Homework_Assignment_18&amp;diff=16284&amp;oldid=prev"/>
		<updated>2017-03-28T13:12:26Z</updated>

		<summary type="html">&lt;p&gt;&lt;span dir=&quot;auto&quot;&gt;&lt;span class=&quot;autocomment&quot;&gt;Doing&lt;/span&gt;&lt;/span&gt;&lt;/p&gt;
&lt;table style=&quot;background-color: #fff; color: #202122;&quot; data-mw=&quot;interface&quot;&gt;
				&lt;col class=&quot;diff-marker&quot; /&gt;
				&lt;col class=&quot;diff-content&quot; /&gt;
				&lt;col class=&quot;diff-marker&quot; /&gt;
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				&lt;tr class=&quot;diff-title&quot; lang=&quot;en&quot;&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: #fff; color: #202122; text-align: center;&quot;&gt;← Older revision&lt;/td&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: #fff; color: #202122; text-align: center;&quot;&gt;Revision as of 09:12, 28 March 2017&lt;/td&gt;
				&lt;/tr&gt;&lt;tr&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 6:&lt;/td&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 6:&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;Ponder the questions in sections 34 and 35, yet solve and submit only the following problems:&lt;/div&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;Ponder the questions in sections 34 and 35, yet solve and submit only the following problems:&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;br /&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;br /&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot; data-marker=&quot;−&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;u&amp;gt;&#039;&#039;&#039;Problem A.&#039;&#039;&#039;&amp;lt;/u&amp;gt; Consider &amp;lt;math&amp;gt;S^{n-1}&amp;lt;/math&amp;gt; at the boundary of &amp;lt;math&amp;gt;D^n\subset{\mathbb R}^n&amp;lt;/math&amp;gt;, taken with its standard orientation, and let &amp;lt;math&amp;gt;\iota\colon S^{n-1}\to{\mathbb R}^n&amp;lt;/math&amp;gt; be the inclusion map. Let &amp;lt;math&amp;gt;\omega=\iota^\ast\left(\&lt;del style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;sum_ix_idx_1&lt;/del&gt;\wedge\dots\wedge\widehat{dx_i}\wedge\dots\wedge dx_n\right)\in\Omega^{\text{top}}(S^{n-1})&amp;lt;/math&amp;gt;. Prove that if &amp;lt;math&amp;gt;(v_1,\ldots,v_{n-1})&amp;lt;/math&amp;gt; is a positively oriented basis of &amp;lt;math&amp;gt;T_xS^{n-1}&amp;lt;/math&amp;gt; for some &amp;lt;math&amp;gt;x\in S^{n-1}&amp;lt;/math&amp;gt;, then &amp;lt;math&amp;gt;\omega(v_1,\ldots,v_{n-1})&amp;lt;/math&amp;gt; is the volume of the &amp;lt;math&amp;gt;(n-1)&amp;lt;/math&amp;gt;-dimensional parallelepiped spanned by &amp;lt;math&amp;gt;v_1,\ldots,v_{n-1}&amp;lt;/math&amp;gt;, and hence for any smooth function &amp;lt;math&amp;gt;f&amp;lt;/math&amp;gt; on &amp;lt;math&amp;gt;S^{n-1}&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;\int_{S^{n-1}}f\omega = \int_{S^{n-1}}fdV&amp;lt;/math&amp;gt;, where the latter integral is integration relative to the volume, as defined a long time ago.&lt;/div&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot; data-marker=&quot;+&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;u&amp;gt;&#039;&#039;&#039;Problem A.&#039;&#039;&#039;&amp;lt;/u&amp;gt; Consider &amp;lt;math&amp;gt;S^{n-1}&amp;lt;/math&amp;gt; at the boundary of &amp;lt;math&amp;gt;D^n\subset{\mathbb R}^n&amp;lt;/math&amp;gt;, taken with its standard orientation, and let &amp;lt;math&amp;gt;\iota\colon S^{n-1}\to{\mathbb R}^n&amp;lt;/math&amp;gt; be the inclusion map. Let &amp;lt;math&amp;gt;\omega=\iota^\ast\left(\&lt;ins style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;sum_i(-1)^ix_idx_1&lt;/ins&gt;\wedge\dots\wedge\widehat{dx_i}\wedge\dots\wedge dx_n\right)\in\Omega^{\text{top}}(S^{n-1})&amp;lt;/math&amp;gt;. Prove that if &amp;lt;math&amp;gt;(v_1,\ldots,v_{n-1})&amp;lt;/math&amp;gt; is a positively oriented basis of &amp;lt;math&amp;gt;T_xS^{n-1}&amp;lt;/math&amp;gt; for some &amp;lt;math&amp;gt;x\in S^{n-1}&amp;lt;/math&amp;gt;, then &amp;lt;math&amp;gt;\omega(v_1,\ldots,v_{n-1})&amp;lt;/math&amp;gt; is the volume of the &amp;lt;math&amp;gt;(n-1)&amp;lt;/math&amp;gt;-dimensional parallelepiped spanned by &amp;lt;math&amp;gt;v_1,\ldots,v_{n-1}&amp;lt;/math&amp;gt;, and hence for any smooth function &amp;lt;math&amp;gt;f&amp;lt;/math&amp;gt; on &amp;lt;math&amp;gt;S^{n-1}&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;\int_{S^{n-1}}f\omega = \int_{S^{n-1}}fdV&amp;lt;/math&amp;gt;, where the latter integral is integration relative to the volume, as defined a long time ago.&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-empty diff-side-deleted&quot;&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot; data-marker=&quot;+&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;br /&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-empty diff-side-deleted&quot;&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot; data-marker=&quot;+&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&#039;&#039;&#039;Note.&#039;&#039;&#039; Earlier I made a sign mistake in the definition of and wrote &amp;lt;math&amp;gt;\omega=\iota^\ast\left(\sum_ix_idx_1\wedge\dots\wedge\widehat{dx_i}\wedge\dots\wedge dx_n\right)\in\Omega^{\text{top}}(S^{n-1})&amp;lt;/math&amp;gt;. I&#039;d like to thank the students who emailed me the correction.&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;br /&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;br /&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;u&amp;gt;&#039;&#039;&#039;Problem B&#039;&#039;&#039;&amp;lt;/u&amp;gt;  (an alternative definition for &quot;orientation&quot;). Define a &quot;norientation&quot; (&quot;new orientation&quot;) of a vector space &amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt; to be a function &amp;lt;math&amp;gt;\nu\colon\{\text{ordered bases of }V\}\to\{\pm 1\}&amp;lt;/math&amp;gt; which satisfies &amp;lt;math&amp;gt;\nu(v)=\operatorname{sign}(\det(C^u_v))\nu(u)&amp;lt;/math&amp;gt;, whenever &amp;lt;math&amp;gt;u&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; are ordered bases of &amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;C^u_v&amp;lt;/math&amp;gt; is the change-of-basis matrix between them.&lt;/div&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;u&amp;gt;&#039;&#039;&#039;Problem B&#039;&#039;&#039;&amp;lt;/u&amp;gt;  (an alternative definition for &quot;orientation&quot;). Define a &quot;norientation&quot; (&quot;new orientation&quot;) of a vector space &amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt; to be a function &amp;lt;math&amp;gt;\nu\colon\{\text{ordered bases of }V\}\to\{\pm 1\}&amp;lt;/math&amp;gt; which satisfies &amp;lt;math&amp;gt;\nu(v)=\operatorname{sign}(\det(C^u_v))\nu(u)&amp;lt;/math&amp;gt;, whenever &amp;lt;math&amp;gt;u&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; are ordered bases of &amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;C^u_v&amp;lt;/math&amp;gt; is the change-of-basis matrix between them.&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;/table&gt;</summary>
		<author><name>Drorbn</name></author>
	</entry>
	<entry>
		<id>https://drorbn.net/index.php?title=1617-257/Homework_Assignment_18&amp;diff=16258&amp;oldid=prev</id>
		<title>Drorbn at 19:24, 22 March 2017</title>
		<link rel="alternate" type="text/html" href="https://drorbn.net/index.php?title=1617-257/Homework_Assignment_18&amp;diff=16258&amp;oldid=prev"/>
		<updated>2017-03-22T19:24:25Z</updated>

		<summary type="html">&lt;p&gt;&lt;/p&gt;
&lt;table style=&quot;background-color: #fff; color: #202122;&quot; data-mw=&quot;interface&quot;&gt;
				&lt;col class=&quot;diff-marker&quot; /&gt;
				&lt;col class=&quot;diff-content&quot; /&gt;
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				&lt;tr class=&quot;diff-title&quot; lang=&quot;en&quot;&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: #fff; color: #202122; text-align: center;&quot;&gt;← Older revision&lt;/td&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: #fff; color: #202122; text-align: center;&quot;&gt;Revision as of 15:24, 22 March 2017&lt;/td&gt;
				&lt;/tr&gt;&lt;tr&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 1:&lt;/td&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 1:&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;{{1617-257/Navigation}}&lt;/div&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;{{1617-257/Navigation}}&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot; data-marker=&quot;−&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;{{In Preparation}}&lt;/div&gt;&lt;/td&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-empty diff-side-added&quot;&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;==Reading==&lt;/div&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;==Reading==&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;Read, reread and rereread your notes to this point, and make sure that you really, really really, really really really understand everything in them. Do the same every week! Also, read, reread and rereread sections 33-38 (skip 36) of Munkres&#039; book to the same standard of understanding. Remember that reading math isn&#039;t like reading a novel! If you read a novel and miss a few details most likely you&#039;ll still understand the novel. But if you miss a few details in a math text, often you&#039;ll miss everything that follows. So reading math takes reading and rereading and rerereading and a lot of thought about what you&#039;ve read. Also, preread section 39, just to get a feel for the future.&lt;/div&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;Read, reread and rereread your notes to this point, and make sure that you really, really really, really really really understand everything in them. Do the same every week! Also, read, reread and rereread sections 33-38 (skip 36) of Munkres&#039; book to the same standard of understanding. Remember that reading math isn&#039;t like reading a novel! If you read a novel and miss a few details most likely you&#039;ll still understand the novel. But if you miss a few details in a math text, often you&#039;ll miss everything that follows. So reading math takes reading and rereading and rerereading and a lot of thought about what you&#039;ve read. Also, preread section 39, just to get a feel for the future.&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;/table&gt;</summary>
		<author><name>Drorbn</name></author>
	</entry>
	<entry>
		<id>https://drorbn.net/index.php?title=1617-257/Homework_Assignment_18&amp;diff=16257&amp;oldid=prev</id>
		<title>Drorbn: /* Doing */</title>
		<link rel="alternate" type="text/html" href="https://drorbn.net/index.php?title=1617-257/Homework_Assignment_18&amp;diff=16257&amp;oldid=prev"/>
		<updated>2017-03-22T19:24:02Z</updated>

		<summary type="html">&lt;p&gt;&lt;span dir=&quot;auto&quot;&gt;&lt;span class=&quot;autocomment&quot;&gt;Doing&lt;/span&gt;&lt;/span&gt;&lt;/p&gt;
&lt;table style=&quot;background-color: #fff; color: #202122;&quot; data-mw=&quot;interface&quot;&gt;
				&lt;col class=&quot;diff-marker&quot; /&gt;
				&lt;col class=&quot;diff-content&quot; /&gt;
				&lt;col class=&quot;diff-marker&quot; /&gt;
				&lt;col class=&quot;diff-content&quot; /&gt;
				&lt;tr class=&quot;diff-title&quot; lang=&quot;en&quot;&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: #fff; color: #202122; text-align: center;&quot;&gt;← Older revision&lt;/td&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: #fff; color: #202122; text-align: center;&quot;&gt;Revision as of 15:24, 22 March 2017&lt;/td&gt;
				&lt;/tr&gt;&lt;tr&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 9:&lt;/td&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 9:&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;u&amp;gt;&#039;&#039;&#039;Problem A.&#039;&#039;&#039;&amp;lt;/u&amp;gt; Consider &amp;lt;math&amp;gt;S^{n-1}&amp;lt;/math&amp;gt; at the boundary of &amp;lt;math&amp;gt;D^n\subset{\mathbb R}^n&amp;lt;/math&amp;gt;, taken with its standard orientation, and let &amp;lt;math&amp;gt;\iota\colon S^{n-1}\to{\mathbb R}^n&amp;lt;/math&amp;gt; be the inclusion map. Let &amp;lt;math&amp;gt;\omega=\iota^\ast\left(\sum_ix_idx_1\wedge\dots\wedge\widehat{dx_i}\wedge\dots\wedge dx_n\right)\in\Omega^{\text{top}}(S^{n-1})&amp;lt;/math&amp;gt;. Prove that if &amp;lt;math&amp;gt;(v_1,\ldots,v_{n-1})&amp;lt;/math&amp;gt; is a positively oriented basis of &amp;lt;math&amp;gt;T_xS^{n-1}&amp;lt;/math&amp;gt; for some &amp;lt;math&amp;gt;x\in S^{n-1}&amp;lt;/math&amp;gt;, then &amp;lt;math&amp;gt;\omega(v_1,\ldots,v_{n-1})&amp;lt;/math&amp;gt; is the volume of the &amp;lt;math&amp;gt;(n-1)&amp;lt;/math&amp;gt;-dimensional parallelepiped spanned by &amp;lt;math&amp;gt;v_1,\ldots,v_{n-1}&amp;lt;/math&amp;gt;, and hence for any smooth function &amp;lt;math&amp;gt;f&amp;lt;/math&amp;gt; on &amp;lt;math&amp;gt;S^{n-1}&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;\int_{S^{n-1}}f\omega = \int_{S^{n-1}}fdV&amp;lt;/math&amp;gt;, where the latter integral is integration relative to the volume, as defined a long time ago.&lt;/div&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;u&amp;gt;&#039;&#039;&#039;Problem A.&#039;&#039;&#039;&amp;lt;/u&amp;gt; Consider &amp;lt;math&amp;gt;S^{n-1}&amp;lt;/math&amp;gt; at the boundary of &amp;lt;math&amp;gt;D^n\subset{\mathbb R}^n&amp;lt;/math&amp;gt;, taken with its standard orientation, and let &amp;lt;math&amp;gt;\iota\colon S^{n-1}\to{\mathbb R}^n&amp;lt;/math&amp;gt; be the inclusion map. Let &amp;lt;math&amp;gt;\omega=\iota^\ast\left(\sum_ix_idx_1\wedge\dots\wedge\widehat{dx_i}\wedge\dots\wedge dx_n\right)\in\Omega^{\text{top}}(S^{n-1})&amp;lt;/math&amp;gt;. Prove that if &amp;lt;math&amp;gt;(v_1,\ldots,v_{n-1})&amp;lt;/math&amp;gt; is a positively oriented basis of &amp;lt;math&amp;gt;T_xS^{n-1}&amp;lt;/math&amp;gt; for some &amp;lt;math&amp;gt;x\in S^{n-1}&amp;lt;/math&amp;gt;, then &amp;lt;math&amp;gt;\omega(v_1,\ldots,v_{n-1})&amp;lt;/math&amp;gt; is the volume of the &amp;lt;math&amp;gt;(n-1)&amp;lt;/math&amp;gt;-dimensional parallelepiped spanned by &amp;lt;math&amp;gt;v_1,\ldots,v_{n-1}&amp;lt;/math&amp;gt;, and hence for any smooth function &amp;lt;math&amp;gt;f&amp;lt;/math&amp;gt; on &amp;lt;math&amp;gt;S^{n-1}&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;\int_{S^{n-1}}f\omega = \int_{S^{n-1}}fdV&amp;lt;/math&amp;gt;, where the latter integral is integration relative to the volume, as defined a long time ago.&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;br /&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;br /&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot; data-marker=&quot;−&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;u&amp;gt;&#039;&#039;&#039;Problem B&#039;&#039;&#039;&amp;lt;/u&amp;gt;  (an alternative definition for &quot;orientation&quot;). Define a norientation (&quot;new orientation&quot;) of a vector space &amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt; to be a function &amp;lt;math&amp;gt;\nu\colon\{\text{ordered bases of }V\}\to\{\pm 1\}&amp;lt;/math&amp;gt; which satisfies &amp;lt;math&amp;gt;\nu(v)=\operatorname{sign}(\det(C^u_v))\nu(u)&amp;lt;/math&amp;gt;, whenever &amp;lt;math&amp;gt;u&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; are ordered bases of &amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;C^u_v&amp;lt;/math&amp;gt; is the change-of-basis matrix between them.&lt;/div&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot; data-marker=&quot;+&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;u&amp;gt;&#039;&#039;&#039;Problem B&#039;&#039;&#039;&amp;lt;/u&amp;gt;  (an alternative definition for &quot;orientation&quot;). Define a &lt;ins style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;&quot;&lt;/ins&gt;norientation&lt;ins style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;&quot;&lt;/ins&gt; (&quot;new orientation&quot;) of a vector space &amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt; to be a function &amp;lt;math&amp;gt;\nu\colon\{\text{ordered bases of }V\}\to\{\pm 1\}&amp;lt;/math&amp;gt; which satisfies &amp;lt;math&amp;gt;\nu(v)=\operatorname{sign}(\det(C^u_v))\nu(u)&amp;lt;/math&amp;gt;, whenever &amp;lt;math&amp;gt;u&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; are ordered bases of &amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;C^u_v&amp;lt;/math&amp;gt; is the change-of-basis matrix between them.&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;ol&amp;gt;&lt;/div&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;ol&amp;gt;&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;li&amp;gt; Explain how if &amp;lt;math&amp;gt;\dim(V)&amp;gt;1&amp;lt;/math&amp;gt;, a norientation is equivalent to an orientation.&lt;/div&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;li&amp;gt; Explain how if &amp;lt;math&amp;gt;\dim(V)&amp;gt;1&amp;lt;/math&amp;gt;, a norientation is equivalent to an orientation.&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 15:&lt;/td&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 15:&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;li&amp;gt; Explain how a norientation of &amp;lt;math&amp;gt;M&amp;lt;/math&amp;gt; induces a norientation of &amp;lt;math&amp;gt;\partial M&amp;lt;/math&amp;gt;.&lt;/div&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;li&amp;gt; Explain how a norientation of &amp;lt;math&amp;gt;M&amp;lt;/math&amp;gt; induces a norientation of &amp;lt;math&amp;gt;\partial M&amp;lt;/math&amp;gt;.&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;li&amp;gt; What is a &amp;lt;math&amp;gt;0&amp;lt;/math&amp;gt;-dimensional manifold? What is a norientation of a &amp;lt;math&amp;gt;0&amp;lt;/math&amp;gt;-dimensional manifold?&lt;/div&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;li&amp;gt; What is a &amp;lt;math&amp;gt;0&amp;lt;/math&amp;gt;-dimensional manifold? What is a norientation of a &amp;lt;math&amp;gt;0&amp;lt;/math&amp;gt;-dimensional manifold?&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-empty diff-side-deleted&quot;&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot; data-marker=&quot;+&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;li&amp;gt; What is the integral of a &amp;lt;math&amp;gt;0&amp;lt;/math&amp;gt;-form on a &amp;lt;math&amp;gt;0&amp;lt;/math&amp;gt;-dimensional noriented manifold?&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;li&amp;gt; What is &amp;lt;math&amp;gt;\partial[0,1]&amp;lt;/math&amp;gt; as a noriented &amp;lt;math&amp;gt;0&amp;lt;/math&amp;gt;-manifold? (Assume that &amp;lt;math&amp;gt;[0,1]&amp;lt;/math&amp;gt; is endowed with its &quot;positive&quot; or &quot;standard&quot; orientation/norientation).&lt;/div&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;li&amp;gt; What is &amp;lt;math&amp;gt;\partial[0,1]&amp;lt;/math&amp;gt; as a noriented &amp;lt;math&amp;gt;0&amp;lt;/math&amp;gt;-manifold? (Assume that &amp;lt;math&amp;gt;[0,1]&amp;lt;/math&amp;gt; is endowed with its &quot;positive&quot; or &quot;standard&quot; orientation/norientation).&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;/ol&amp;gt;&lt;/div&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;/ol&amp;gt;&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;/table&gt;</summary>
		<author><name>Drorbn</name></author>
	</entry>
	<entry>
		<id>https://drorbn.net/index.php?title=1617-257/Homework_Assignment_18&amp;diff=16230&amp;oldid=prev</id>
		<title>Drorbn: /* Doing */</title>
		<link rel="alternate" type="text/html" href="https://drorbn.net/index.php?title=1617-257/Homework_Assignment_18&amp;diff=16230&amp;oldid=prev"/>
		<updated>2017-03-20T20:38:27Z</updated>

		<summary type="html">&lt;p&gt;&lt;span dir=&quot;auto&quot;&gt;&lt;span class=&quot;autocomment&quot;&gt;Doing&lt;/span&gt;&lt;/span&gt;&lt;/p&gt;
&lt;table style=&quot;background-color: #fff; color: #202122;&quot; data-mw=&quot;interface&quot;&gt;
				&lt;col class=&quot;diff-marker&quot; /&gt;
				&lt;col class=&quot;diff-content&quot; /&gt;
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				&lt;col class=&quot;diff-content&quot; /&gt;
				&lt;tr class=&quot;diff-title&quot; lang=&quot;en&quot;&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: #fff; color: #202122; text-align: center;&quot;&gt;← Older revision&lt;/td&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: #fff; color: #202122; text-align: center;&quot;&gt;Revision as of 16:38, 20 March 2017&lt;/td&gt;
				&lt;/tr&gt;&lt;tr&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 7:&lt;/td&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 7:&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;Ponder the questions in sections 34 and 35, yet solve and submit only the following problems:&lt;/div&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;Ponder the questions in sections 34 and 35, yet solve and submit only the following problems:&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;br /&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;br /&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot; data-marker=&quot;−&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;u&amp;gt;&#039;&#039;&#039;Problem &lt;del style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;1&lt;/del&gt;.&#039;&#039;&#039;&amp;lt;/u&amp;gt; Consider &amp;lt;math&amp;gt;S^{n-1}&amp;lt;/math&amp;gt; at the boundary of &amp;lt;math&amp;gt;D^n\subset{\mathbb R}^n&amp;lt;/math&amp;gt;, taken with its standard orientation, and let &amp;lt;math&amp;gt;\iota\colon S^{n-1}\to{\mathbb R}^n&amp;lt;/math&amp;gt; be the inclusion map. Let &amp;lt;math&amp;gt;\omega=\iota^\ast\left(\sum_ix_idx_1\wedge\dots\wedge\widehat{dx_i}\wedge\dots\wedge dx_n\right)\in\Omega^{\text{top}}(S^{n-1})&amp;lt;/math&amp;gt;. Prove that if &amp;lt;math&amp;gt;(v_1,\ldots,v_{n-1})&amp;lt;/math&amp;gt; is a positively oriented basis of &amp;lt;math&amp;gt;T_xS^{n-1}&amp;lt;/math&amp;gt; for some &amp;lt;math&amp;gt;x\in S^{n-1}&amp;lt;/math&amp;gt;, then &amp;lt;math&amp;gt;\omega(v_1,\ldots,v_{n-1})&amp;lt;/math&amp;gt; is the volume of the &amp;lt;math&amp;gt;(n-1)&amp;lt;/math&amp;gt;-dimensional parallelepiped spanned by &amp;lt;math&amp;gt;v_1,\ldots,v_{n-1}&amp;lt;/math&amp;gt;, and hence for any smooth function &amp;lt;math&amp;gt;f&amp;lt;/math&amp;gt; on &amp;lt;math&amp;gt;S^{n-1}&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;\int_{S^{n-1}}f\omega = \int_{S^{n-1}}fdV&amp;lt;/math&amp;gt;, where the latter integral is integration relative to the volume, as defined a long time ago.&lt;/div&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot; data-marker=&quot;+&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;u&amp;gt;&#039;&#039;&#039;Problem &lt;ins style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;A&lt;/ins&gt;.&#039;&#039;&#039;&amp;lt;/u&amp;gt; Consider &amp;lt;math&amp;gt;S^{n-1}&amp;lt;/math&amp;gt; at the boundary of &amp;lt;math&amp;gt;D^n\subset{\mathbb R}^n&amp;lt;/math&amp;gt;, taken with its standard orientation, and let &amp;lt;math&amp;gt;\iota\colon S^{n-1}\to{\mathbb R}^n&amp;lt;/math&amp;gt; be the inclusion map. Let &amp;lt;math&amp;gt;\omega=\iota^\ast\left(\sum_ix_idx_1\wedge\dots\wedge\widehat{dx_i}\wedge\dots\wedge dx_n\right)\in\Omega^{\text{top}}(S^{n-1})&amp;lt;/math&amp;gt;. Prove that if &amp;lt;math&amp;gt;(v_1,\ldots,v_{n-1})&amp;lt;/math&amp;gt; is a positively oriented basis of &amp;lt;math&amp;gt;T_xS^{n-1}&amp;lt;/math&amp;gt; for some &amp;lt;math&amp;gt;x\in S^{n-1}&amp;lt;/math&amp;gt;, then &amp;lt;math&amp;gt;\omega(v_1,\ldots,v_{n-1})&amp;lt;/math&amp;gt; is the volume of the &amp;lt;math&amp;gt;(n-1)&amp;lt;/math&amp;gt;-dimensional parallelepiped spanned by &amp;lt;math&amp;gt;v_1,\ldots,v_{n-1}&amp;lt;/math&amp;gt;, and hence for any smooth function &amp;lt;math&amp;gt;f&amp;lt;/math&amp;gt; on &amp;lt;math&amp;gt;S^{n-1}&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;\int_{S^{n-1}}f\omega = \int_{S^{n-1}}fdV&amp;lt;/math&amp;gt;, where the latter integral is integration relative to the volume, as defined a long time ago.&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;br /&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;br /&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot; data-marker=&quot;−&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;u&amp;gt;&#039;&#039;&#039;Problem &lt;del style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;2&lt;/del&gt;&#039;&#039;&#039;&amp;lt;/u&amp;gt;  (an alternative definition for &quot;orientation&quot;). Define a norientation (&quot;new orientation&quot;) of a vector space &amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt; to be a function &amp;lt;math&amp;gt;\nu\colon\{\text{ordered bases of }V\}\to\{\pm 1\}&amp;lt;/math&amp;gt; which satisfies &amp;lt;math&amp;gt;\nu(v)=\operatorname{sign}(\det(C^u_v))\nu(u)&amp;lt;/math&amp;gt;, whenever &amp;lt;math&amp;gt;u&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; are ordered bases of &amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;C^u_v&amp;lt;/math&amp;gt; is the change-of-basis matrix between them.&lt;/div&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot; data-marker=&quot;+&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;u&amp;gt;&#039;&#039;&#039;Problem &lt;ins style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;B&lt;/ins&gt;&#039;&#039;&#039;&amp;lt;/u&amp;gt;  (an alternative definition for &quot;orientation&quot;). Define a norientation (&quot;new orientation&quot;) of a vector space &amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt; to be a function &amp;lt;math&amp;gt;\nu\colon\{\text{ordered bases of }V\}\to\{\pm 1\}&amp;lt;/math&amp;gt; which satisfies &amp;lt;math&amp;gt;\nu(v)=\operatorname{sign}(\det(C^u_v))\nu(u)&amp;lt;/math&amp;gt;, whenever &amp;lt;math&amp;gt;u&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; are ordered bases of &amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;C^u_v&amp;lt;/math&amp;gt; is the change-of-basis matrix between them.&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;ol&amp;gt;&lt;/div&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;ol&amp;gt;&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;li&amp;gt; Explain how if &amp;lt;math&amp;gt;\dim(V)&amp;gt;1&amp;lt;/math&amp;gt;, a norientation is equivalent to an orientation.&lt;/div&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;li&amp;gt; Explain how if &amp;lt;math&amp;gt;\dim(V)&amp;gt;1&amp;lt;/math&amp;gt;, a norientation is equivalent to an orientation.&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 16:&lt;/td&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 16:&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;li&amp;gt; What is a &amp;lt;math&amp;gt;0&amp;lt;/math&amp;gt;-dimensional manifold? What is a norientation of a &amp;lt;math&amp;gt;0&amp;lt;/math&amp;gt;-dimensional manifold?&lt;/div&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;li&amp;gt; What is a &amp;lt;math&amp;gt;0&amp;lt;/math&amp;gt;-dimensional manifold? What is a norientation of a &amp;lt;math&amp;gt;0&amp;lt;/math&amp;gt;-dimensional manifold?&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;li&amp;gt; What is &amp;lt;math&amp;gt;\partial[0,1]&amp;lt;/math&amp;gt; as a noriented &amp;lt;math&amp;gt;0&amp;lt;/math&amp;gt;-manifold? (Assume that &amp;lt;math&amp;gt;[0,1]&amp;lt;/math&amp;gt; is endowed with its &quot;positive&quot; or &quot;standard&quot; orientation/norientation).&lt;/div&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;li&amp;gt; What is &amp;lt;math&amp;gt;\partial[0,1]&amp;lt;/math&amp;gt; as a noriented &amp;lt;math&amp;gt;0&amp;lt;/math&amp;gt;-manifold? (Assume that &amp;lt;math&amp;gt;[0,1]&amp;lt;/math&amp;gt; is endowed with its &quot;positive&quot; or &quot;standard&quot; orientation/norientation).&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-empty diff-side-deleted&quot;&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot; data-marker=&quot;+&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;/ol&amp;gt;&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-empty diff-side-deleted&quot;&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot; data-marker=&quot;+&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;br /&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-empty diff-side-deleted&quot;&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot; data-marker=&quot;+&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;u&amp;gt;&#039;&#039;&#039;Problem C&#039;&#039;&#039;.&amp;lt;/u&amp;gt; Let &amp;lt;math&amp;gt;\omega=ydx\in\Omega^1({\mathbb R}^2_{x,y})&amp;lt;/math&amp;gt;.&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-empty diff-side-deleted&quot;&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot; data-marker=&quot;+&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;ol&amp;gt;&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-empty diff-side-deleted&quot;&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot; data-marker=&quot;+&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;li&amp;gt; Let &amp;lt;math&amp;gt;\Gamma&amp;lt;/math&amp;gt; be the graph in &amp;lt;math&amp;gt;{\mathbb R}^2_{x,y}&amp;lt;/math&amp;gt; of some smooth function &amp;lt;math&amp;gt;f\colon[a,b]\to{\mathbb R}&amp;lt;/math&amp;gt;. Using the inclusion of &amp;lt;math&amp;gt;\Gamma&amp;lt;/math&amp;gt; to &amp;lt;math&amp;gt;{\mathbb R}^2_{x,y}&amp;lt;/math&amp;gt;, consider &amp;lt;math&amp;gt;\omega&amp;lt;/math&amp;gt; also as a 1-form on &amp;lt;math&amp;gt;\Gamma&amp;lt;/math&amp;gt;. What is &amp;lt;math&amp;gt;\int_\Gamma\omega&amp;lt;/math&amp;gt;?&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-empty diff-side-deleted&quot;&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot; data-marker=&quot;+&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;li&amp;gt; Prove that if &amp;lt;math&amp;gt;E&amp;lt;/math&amp;gt; is an ellipse in &amp;lt;math&amp;gt;{\mathbb R}^2_{x,y}&amp;lt;/math&amp;gt; (of whatever major and minor axes, placed anywhere and tilted as you please), then &amp;lt;math&amp;gt;\int_{\partial E}\omega&amp;lt;/math&amp;gt; is the area of &amp;lt;math&amp;gt;E&amp;lt;/math&amp;gt;.&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-empty diff-side-deleted&quot;&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot; data-marker=&quot;+&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;li&amp;gt; Compute also &amp;lt;math&amp;gt;d\omega&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\int_Ed\omega&amp;lt;/math&amp;gt;.&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;/ol&amp;gt;&lt;/div&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;/ol&amp;gt;&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;br /&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;br /&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;/table&gt;</summary>
		<author><name>Drorbn</name></author>
	</entry>
	<entry>
		<id>https://drorbn.net/index.php?title=1617-257/Homework_Assignment_18&amp;diff=16228&amp;oldid=prev</id>
		<title>Drorbn: /* Doing */</title>
		<link rel="alternate" type="text/html" href="https://drorbn.net/index.php?title=1617-257/Homework_Assignment_18&amp;diff=16228&amp;oldid=prev"/>
		<updated>2017-03-20T20:29:28Z</updated>

		<summary type="html">&lt;p&gt;&lt;span dir=&quot;auto&quot;&gt;&lt;span class=&quot;autocomment&quot;&gt;Doing&lt;/span&gt;&lt;/span&gt;&lt;/p&gt;
&lt;table style=&quot;background-color: #fff; color: #202122;&quot; data-mw=&quot;interface&quot;&gt;
				&lt;col class=&quot;diff-marker&quot; /&gt;
				&lt;col class=&quot;diff-content&quot; /&gt;
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				&lt;tr class=&quot;diff-title&quot; lang=&quot;en&quot;&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: #fff; color: #202122; text-align: center;&quot;&gt;← Older revision&lt;/td&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: #fff; color: #202122; text-align: center;&quot;&gt;Revision as of 16:29, 20 March 2017&lt;/td&gt;
				&lt;/tr&gt;&lt;tr&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 7:&lt;/td&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 7:&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;Ponder the questions in sections 34 and 35, yet solve and submit only the following problems:&lt;/div&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;Ponder the questions in sections 34 and 35, yet solve and submit only the following problems:&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;br /&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;br /&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot; data-marker=&quot;−&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;u&amp;gt;&#039;&#039;&#039;Problem 1&#039;&#039;&#039;&amp;lt;/u&amp;gt; Consider &amp;lt;math&amp;gt;S^{n-1}&amp;lt;/math&amp;gt; at the boundary of &amp;lt;math&amp;gt;D^n\subset{\mathbb R}^n&amp;lt;/math&amp;gt;, taken with its standard orientation, and let &amp;lt;math&amp;gt;\iota\colon S^{n-1}\to{\mathbb R}^n&amp;lt;/math&amp;gt; be the inclusion map. Let &amp;lt;math&amp;gt;\omega=\iota^\ast\left(\sum_ix_idx_1\wedge\dots\wedge\widehat{dx_i}\wedge\dots\wedge dx_n\right)\in\Omega^{\text{top}}(S^{n-1})&amp;lt;/math&amp;gt;. Prove that if &amp;lt;math&amp;gt;(v_1,\ldots,v_{n-1})&amp;lt;/math&amp;gt; is a positively oriented basis of &amp;lt;math&amp;gt;T_xS^{n-1}&amp;lt;/math&amp;gt; for some &amp;lt;math&amp;gt;x\in S^{n-1}&amp;lt;/math&amp;gt;, then &amp;lt;math&amp;gt;\omega(v_1,\ldots,v_{n-1})&amp;lt;/math&amp;gt; is the volume of the &amp;lt;math&amp;gt;(n-1)&amp;lt;/math&amp;gt;-dimensional parallelepiped spanned by &amp;lt;math&amp;gt;v_1,\ldots,v_{n-1}&amp;lt;/math&amp;gt;, and hence for any smooth function &amp;lt;math&amp;gt;f&amp;lt;/math&amp;gt; on &amp;lt;math&amp;gt;S^{n-1}&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;\int_{S^{n-1}}f\omega = \int_{S^{n-1}}fdV&amp;lt;/math&amp;gt;, where the latter integral is integration relative to the volume, as defined a long time ago.&lt;/div&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot; data-marker=&quot;+&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;u&amp;gt;&#039;&#039;&#039;Problem 1&lt;ins style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;.&lt;/ins&gt;&#039;&#039;&#039;&amp;lt;/u&amp;gt; Consider &amp;lt;math&amp;gt;S^{n-1}&amp;lt;/math&amp;gt; at the boundary of &amp;lt;math&amp;gt;D^n\subset{\mathbb R}^n&amp;lt;/math&amp;gt;, taken with its standard orientation, and let &amp;lt;math&amp;gt;\iota\colon S^{n-1}\to{\mathbb R}^n&amp;lt;/math&amp;gt; be the inclusion map. Let &amp;lt;math&amp;gt;\omega=\iota^\ast\left(\sum_ix_idx_1\wedge\dots\wedge\widehat{dx_i}\wedge\dots\wedge dx_n\right)\in\Omega^{\text{top}}(S^{n-1})&amp;lt;/math&amp;gt;. Prove that if &amp;lt;math&amp;gt;(v_1,\ldots,v_{n-1})&amp;lt;/math&amp;gt; is a positively oriented basis of &amp;lt;math&amp;gt;T_xS^{n-1}&amp;lt;/math&amp;gt; for some &amp;lt;math&amp;gt;x\in S^{n-1}&amp;lt;/math&amp;gt;, then &amp;lt;math&amp;gt;\omega(v_1,\ldots,v_{n-1})&amp;lt;/math&amp;gt; is the volume of the &amp;lt;math&amp;gt;(n-1)&amp;lt;/math&amp;gt;-dimensional parallelepiped spanned by &amp;lt;math&amp;gt;v_1,\ldots,v_{n-1}&amp;lt;/math&amp;gt;, and hence for any smooth function &amp;lt;math&amp;gt;f&amp;lt;/math&amp;gt; on &amp;lt;math&amp;gt;S^{n-1}&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;\int_{S^{n-1}}f\omega = \int_{S^{n-1}}fdV&amp;lt;/math&amp;gt;, where the latter integral is integration relative to the volume, as defined a long time ago.&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-empty diff-side-deleted&quot;&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot; data-marker=&quot;+&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;br /&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-empty diff-side-deleted&quot;&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot; data-marker=&quot;+&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;u&amp;gt;&#039;&#039;&#039;Problem 2&#039;&#039;&#039;&amp;lt;/u&amp;gt;  (an alternative definition for &quot;orientation&quot;). Define a norientation (&quot;new orientation&quot;) of a vector space &amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt; to be a function &amp;lt;math&amp;gt;\nu\colon\{\text{ordered bases of }V\}\to\{\pm 1\}&amp;lt;/math&amp;gt; which satisfies &amp;lt;math&amp;gt;\nu(v)=\operatorname{sign}(\det(C^u_v))\nu(u)&amp;lt;/math&amp;gt;, whenever &amp;lt;math&amp;gt;u&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; are ordered bases of &amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;C^u_v&amp;lt;/math&amp;gt; is the change-of-basis matrix between them.&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-empty diff-side-deleted&quot;&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot; data-marker=&quot;+&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;ol&amp;gt;&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-empty diff-side-deleted&quot;&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot; data-marker=&quot;+&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;li&amp;gt; Explain how if &amp;lt;math&amp;gt;\dim(V)&amp;gt;1&amp;lt;/math&amp;gt;, a norientation is equivalent to an orientation.&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-empty diff-side-deleted&quot;&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot; data-marker=&quot;+&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;li&amp;gt; Come up with a reasonable definition of a norientation of a &amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt;-dimensional manifold.&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-empty diff-side-deleted&quot;&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot; data-marker=&quot;+&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;li&amp;gt; Explain how a norientation of &amp;lt;math&amp;gt;M&amp;lt;/math&amp;gt; induces a norientation of &amp;lt;math&amp;gt;\partial M&amp;lt;/math&amp;gt;.&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-empty diff-side-deleted&quot;&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot; data-marker=&quot;+&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;li&amp;gt; What is a &amp;lt;math&amp;gt;0&amp;lt;/math&amp;gt;-dimensional manifold? What is a norientation of a &amp;lt;math&amp;gt;0&amp;lt;/math&amp;gt;-dimensional manifold?&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-empty diff-side-deleted&quot;&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot; data-marker=&quot;+&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;li&amp;gt; What is &amp;lt;math&amp;gt;\partial[0,1]&amp;lt;/math&amp;gt; as a noriented &amp;lt;math&amp;gt;0&amp;lt;/math&amp;gt;-manifold? (Assume that &amp;lt;math&amp;gt;[0,1]&amp;lt;/math&amp;gt; is endowed with its &quot;positive&quot; or &quot;standard&quot; orientation/norientation).&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-empty diff-side-deleted&quot;&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot; data-marker=&quot;+&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;/ol&amp;gt;&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;br /&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;br /&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;==Submission==&lt;/div&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;==Submission==&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;/table&gt;</summary>
		<author><name>Drorbn</name></author>
	</entry>
	<entry>
		<id>https://drorbn.net/index.php?title=1617-257/Homework_Assignment_18&amp;diff=16225&amp;oldid=prev</id>
		<title>Drorbn at 20:15, 20 March 2017</title>
		<link rel="alternate" type="text/html" href="https://drorbn.net/index.php?title=1617-257/Homework_Assignment_18&amp;diff=16225&amp;oldid=prev"/>
		<updated>2017-03-20T20:15:33Z</updated>

		<summary type="html">&lt;p&gt;&lt;/p&gt;
&lt;table style=&quot;background-color: #fff; color: #202122;&quot; data-mw=&quot;interface&quot;&gt;
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				&lt;td colspan=&quot;2&quot; style=&quot;background-color: #fff; color: #202122; text-align: center;&quot;&gt;← Older revision&lt;/td&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: #fff; color: #202122; text-align: center;&quot;&gt;Revision as of 16:15, 20 March 2017&lt;/td&gt;
				&lt;/tr&gt;&lt;tr&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 5:&lt;/td&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 5:&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;br /&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;br /&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;==Doing==&lt;/div&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;==Doing==&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-empty diff-side-deleted&quot;&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot; data-marker=&quot;+&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;Ponder the questions in sections 34 and 35, yet solve and submit only the following problems:&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot; data-marker=&quot;−&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&#039;&#039;&#039;Solve&#039;&#039;&#039; &#039;&#039;all&#039;&#039; the problems in sections 32 and 33, but submit only your solutions of problem &amp;lt;u&amp;gt;3&amp;lt;/u&amp;gt; and &amp;lt;u&amp;gt;5&amp;lt;/u&amp;gt; in section 32 and of problems &amp;lt;u&amp;gt;2&amp;lt;/u&amp;gt; and &amp;lt;u&amp;gt;3&amp;lt;/u&amp;gt; in section 33. In addition, ponder the following&lt;/div&gt;&lt;/td&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-empty diff-side-added&quot;&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;br /&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;br /&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-empty diff-side-deleted&quot;&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot; data-marker=&quot;+&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;u&amp;gt;&#039;&#039;&#039;Problem 1&#039;&#039;&#039;&amp;lt;/u&amp;gt; Consider &amp;lt;math&amp;gt;S^{n-1}&amp;lt;/math&amp;gt; at the boundary of &amp;lt;math&amp;gt;D^n\subset{\mathbb R}^n&amp;lt;/math&amp;gt;, taken with its standard orientation, and let &amp;lt;math&amp;gt;\iota\colon S^{n-1}\to{\mathbb R}^n&amp;lt;/math&amp;gt; be the inclusion map. Let &amp;lt;math&amp;gt;\omega=\iota^\ast\left(\sum_ix_idx_1\wedge\dots\wedge\widehat{dx_i}\wedge\dots\wedge dx_n\right)\in\Omega^{\text{top}}(S^{n-1})&amp;lt;/math&amp;gt;. Prove that if &amp;lt;math&amp;gt;(v_1,\ldots,v_{n-1})&amp;lt;/math&amp;gt; is a positively oriented basis of &amp;lt;math&amp;gt;T_xS^{n-1}&amp;lt;/math&amp;gt; for some &amp;lt;math&amp;gt;x\in S^{n-1}&amp;lt;/math&amp;gt;, then &amp;lt;math&amp;gt;\omega(v_1,\ldots,v_{n-1})&amp;lt;/math&amp;gt; is the volume of the &amp;lt;math&amp;gt;(n-1)&amp;lt;/math&amp;gt;-dimensional parallelepiped spanned by &amp;lt;math&amp;gt;v_1,\ldots,v_{n-1}&amp;lt;/math&amp;gt;, and hence for any smooth function &amp;lt;math&amp;gt;f&amp;lt;/math&amp;gt; on &amp;lt;math&amp;gt;S^{n-1}&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;\int_{S^{n-1}}f\omega = \int_{S^{n-1}}fdV&amp;lt;/math&amp;gt;, where the latter integral is integration relative to the volume, as defined a long time ago.&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot; data-marker=&quot;−&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&#039;&#039;&#039;Challenge Question&#039;&#039;&#039; (do not submit). What was it that you computed, in problem 3 of section 33? Could you have done it without any actual computation?&lt;/div&gt;&lt;/td&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-empty diff-side-added&quot;&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;br /&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;br /&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;==Submission==&lt;/div&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;==Submission==&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;Here and everywhere, &#039;&#039;&#039;neatness counts!!&#039;&#039;&#039; You may be brilliant and you may mean just the right things, but if the teaching assistants will be having hard time deciphering your work they will give up and assume it is wrong.&lt;/div&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;Here and everywhere, &#039;&#039;&#039;neatness counts!!&#039;&#039;&#039; You may be brilliant and you may mean just the right things, but if the teaching assistants will be having hard time deciphering your work they will give up and assume it is wrong.&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;br /&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;br /&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot; data-marker=&quot;−&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;This assignment is due in class on &amp;lt;span style=&quot;color: blue;&quot;&amp;gt;Wednesday March &lt;del style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;22&lt;/del&gt; by 2:10PM&amp;lt;/span&amp;gt;.&lt;/div&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot; data-marker=&quot;+&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;This assignment is due in class on &amp;lt;span style=&quot;color: blue;&quot;&amp;gt;Wednesday March &lt;ins style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;29&lt;/ins&gt; by 2:10PM&amp;lt;/span&amp;gt;.&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;br /&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;br /&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;===&amp;lt;span style=&quot;color: red;&quot;&amp;gt;Important&amp;lt;/span&amp;gt;===&lt;/div&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;===&amp;lt;span style=&quot;color: red;&quot;&amp;gt;Important&amp;lt;/span&amp;gt;===&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;/table&gt;</summary>
		<author><name>Drorbn</name></author>
	</entry>
	<entry>
		<id>https://drorbn.net/index.php?title=1617-257/Homework_Assignment_18&amp;diff=16223&amp;oldid=prev</id>
		<title>Drorbn: Created page with &quot;{{1617-257/Navigation}} {{In Preparation}} ==Reading== Read, reread and rereread your notes to this point, and make sure that you really, really really, really really really u...&quot;</title>
		<link rel="alternate" type="text/html" href="https://drorbn.net/index.php?title=1617-257/Homework_Assignment_18&amp;diff=16223&amp;oldid=prev"/>
		<updated>2017-03-20T16:17:23Z</updated>

		<summary type="html">&lt;p&gt;Created page with &amp;quot;{{1617-257/Navigation}} {{In Preparation}} ==Reading== Read, reread and rereread your notes to this point, and make sure that you really, really really, really really really u...&amp;quot;&lt;/p&gt;
&lt;p&gt;&lt;b&gt;New page&lt;/b&gt;&lt;/p&gt;&lt;div&gt;{{1617-257/Navigation}}&lt;br /&gt;
{{In Preparation}}&lt;br /&gt;
==Reading==&lt;br /&gt;
Read, reread and rereread your notes to this point, and make sure that you really, really really, really really really understand everything in them. Do the same every week! Also, read, reread and rereread sections 33-38 (skip 36) of Munkres&amp;#039; book to the same standard of understanding. Remember that reading math isn&amp;#039;t like reading a novel! If you read a novel and miss a few details most likely you&amp;#039;ll still understand the novel. But if you miss a few details in a math text, often you&amp;#039;ll miss everything that follows. So reading math takes reading and rereading and rerereading and a lot of thought about what you&amp;#039;ve read. Also, preread section 39, just to get a feel for the future.&lt;br /&gt;
&lt;br /&gt;
==Doing==&lt;br /&gt;
&amp;#039;&amp;#039;&amp;#039;Solve&amp;#039;&amp;#039;&amp;#039; &amp;#039;&amp;#039;all&amp;#039;&amp;#039; the problems in sections 32 and 33, but submit only your solutions of problem &amp;lt;u&amp;gt;3&amp;lt;/u&amp;gt; and &amp;lt;u&amp;gt;5&amp;lt;/u&amp;gt; in section 32 and of problems &amp;lt;u&amp;gt;2&amp;lt;/u&amp;gt; and &amp;lt;u&amp;gt;3&amp;lt;/u&amp;gt; in section 33. In addition, ponder the following&lt;br /&gt;
&lt;br /&gt;
&amp;#039;&amp;#039;&amp;#039;Challenge Question&amp;#039;&amp;#039;&amp;#039; (do not submit). What was it that you computed, in problem 3 of section 33? Could you have done it without any actual computation?&lt;br /&gt;
&lt;br /&gt;
==Submission==&lt;br /&gt;
Here and everywhere, &amp;#039;&amp;#039;&amp;#039;neatness counts!!&amp;#039;&amp;#039;&amp;#039; You may be brilliant and you may mean just the right things, but if the teaching assistants will be having hard time deciphering your work they will give up and assume it is wrong.&lt;br /&gt;
&lt;br /&gt;
This assignment is due in class on &amp;lt;span style=&amp;quot;color: blue;&amp;quot;&amp;gt;Wednesday March 22 by 2:10PM&amp;lt;/span&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
===&amp;lt;span style=&amp;quot;color: red;&amp;quot;&amp;gt;Important&amp;lt;/span&amp;gt;===&lt;br /&gt;
&amp;lt;span style=&amp;quot;color: red;&amp;quot;&amp;gt;Please write on your assignment the day of the tutorial when you&amp;#039;d like to pick it up once it is marked (Wednesday or Thursday).&amp;lt;/span&amp;gt;&lt;/div&gt;</summary>
		<author><name>Drorbn</name></author>
	</entry>
</feed>