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	<updated>2026-05-06T17:14:04Z</updated>
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	<entry>
		<id>https://drorbn.net/index.php?title=12-240/Linear_Algebra_-_Why_We_Care&amp;diff=12401</id>
		<title>12-240/Linear Algebra - Why We Care</title>
		<link rel="alternate" type="text/html" href="https://drorbn.net/index.php?title=12-240/Linear_Algebra_-_Why_We_Care&amp;diff=12401"/>
		<updated>2012-10-31T14:32:10Z</updated>

		<summary type="html">&lt;p&gt;Marie: /* Linear Algebra is the Small Scale Theory of &amp;#039;&amp;#039;Everything&amp;#039;&amp;#039; */&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{12-240/Navigation}}&lt;br /&gt;
==Linear Algebra is the Small Scale Theory of &#039;&#039;Everything&#039;&#039;==&lt;br /&gt;
&lt;br /&gt;
* &#039;&#039;&#039;To study the large, start with the small.&#039;&#039;&#039;&lt;br /&gt;
&lt;br /&gt;
* &#039;&#039;&#039;In small scales, every space is a vector space.&#039;&#039;&#039;&lt;br /&gt;
** Indeed if you walk a mile east, a mile north, a mile west and a mile south, you&#039;re back were you started, but if you fly a 1,000 miles east, a 1,000 miles north, a 1,000 miles west and a 1,000 miles south, you&#039;re not back were you started (where will you be?).&lt;br /&gt;
&lt;br /&gt;
* &#039;&#039;&#039;In small scales, every function is a linear function.&#039;&#039;&#039;&lt;br /&gt;
{| align=center&lt;br /&gt;
|- align=center&lt;br /&gt;
|[[Image:06-240-QuiltBeforeMap.png|200px]]&lt;br /&gt;
|&amp;lt;math&amp;gt;\longrightarrow&amp;lt;/math&amp;gt;&lt;br /&gt;
|[[Image:06-240-QuiltAfterMap.png|200px]]&lt;br /&gt;
|&lt;br /&gt;
|- align=center&lt;br /&gt;
|&amp;lt;math&amp;gt;z&amp;lt;/math&amp;gt;&lt;br /&gt;
|&amp;lt;math&amp;gt;\mapsto&amp;lt;/math&amp;gt;&lt;br /&gt;
|&amp;lt;math&amp;gt;z^2&amp;lt;/math&amp;gt;&lt;br /&gt;
|([[06-240/QuiltPlot|code]])&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
* &#039;&#039;&#039;The world doesn&#039;t come with coordinates.&#039;&#039;&#039;&lt;br /&gt;
** Hence whenever we can we work without a basis, and when we do study bases, we study all of them.&lt;br /&gt;
&lt;br /&gt;
See also {{Pensieve Link|Classes/12-240/index.html#MathematicaNotebooks|The Mathematica notebook QuiltPlot}}.&lt;br /&gt;
&lt;br /&gt;
== Lecture notes scanned by [[User:Marie|marie]] ==&lt;br /&gt;
&amp;lt;gallery&amp;gt;&lt;br /&gt;
Image:12-240_Oct30Notes.pdf&lt;br /&gt;
&amp;lt;/gallery&amp;gt;&lt;/div&gt;</summary>
		<author><name>Marie</name></author>
	</entry>
	<entry>
		<id>https://drorbn.net/index.php?title=File:12-240_Oct30Notes.pdf&amp;diff=12400</id>
		<title>File:12-240 Oct30Notes.pdf</title>
		<link rel="alternate" type="text/html" href="https://drorbn.net/index.php?title=File:12-240_Oct30Notes.pdf&amp;diff=12400"/>
		<updated>2012-10-31T14:27:59Z</updated>

		<summary type="html">&lt;p&gt;Marie: Notes for Lecture 14, October 30, 2012. Topics include: nullity, rank, kernel, image, and dimension theorem.&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;Notes for Lecture 14, October 30, 2012. Topics include: nullity, rank, kernel, image, and dimension theorem.&lt;/div&gt;</summary>
		<author><name>Marie</name></author>
	</entry>
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