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		<id>https://drorbn.net/index.php?title=09-240/About_This_Class&amp;diff=7753</id>
		<title>09-240/About This Class</title>
		<link rel="alternate" type="text/html" href="https://drorbn.net/index.php?title=09-240/About_This_Class&amp;diff=7753"/>
		<updated>2009-09-16T04:42:56Z</updated>

		<summary type="html">&lt;p&gt;Bofu2007: /* How to Succeed in this Class */&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{09-240/Navigation}}&lt;br /&gt;
&lt;br /&gt;
===Crucial Information===&lt;br /&gt;
{{09-240/Crucial Information}}&lt;br /&gt;
&lt;br /&gt;
&#039;&#039;&#039;URL:&#039;&#039;&#039; {{SERVER}}/drorbn/index.php?title=09-240.&lt;br /&gt;
&lt;br /&gt;
===Abstract===&lt;br /&gt;
Taken from the Faculty of Arts and Science [http://www.artsandscience.utoronto.ca/ofr/calendar/crs_mat.htm Calendar]:&lt;br /&gt;
&amp;lt;blockquote&amp;gt;&lt;br /&gt;
A theoretical approach to: vector spaces over arbitrary fields including &amp;lt;math&amp;gt;{\mathbb C}&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;{\mathbb Z}_p&amp;lt;/math&amp;gt;. Subspaces, bases and dimension. Linear transformations, matrices, change of basis, similarity, determinants. Polynomials over a field (including unique factorization, resultants). Eigenvalues, eigenvectors, characteristic polynomial, diagonalization. Minimal polynomial, Cayley-Hamilton theorem.&lt;br /&gt;
&amp;lt;/blockquote&amp;gt;&lt;br /&gt;
&lt;br /&gt;
*Prerequisite: MCV4U, MHF4U&lt;br /&gt;
*Co-requisite: MAT157Y1&lt;br /&gt;
&lt;br /&gt;
[[Image:Friedberg_Insel_Spence_Cover.jpg|right|200px]]&lt;br /&gt;
===Text Book(s)===&lt;br /&gt;
Our main text book will be &#039;&#039;Linear Algebra&#039;&#039; (fourth edition) by Friedberg, Insel and Spence, ISBN 0-13-008451-4; it is a required reading. An errata is at http://www.math.ilstu.edu/linalg/errata.html.&lt;br /&gt;
&lt;br /&gt;
I am told that Schaum’s &#039;&#039;Outline of Linear Algebra&#039;&#039;, ISBN 0-07-136200-2, may contain useful examples; it is not a required reading.&lt;br /&gt;
&lt;br /&gt;
===Wiki===&lt;br /&gt;
The class web site is a wiki, as in [http://www.wikipedia.org Wikipedia] - meaning that anyone can and is welcome to edit almost anything and in particular, students can post notes, comments, pictures, whatever. Some rules, though -&lt;br /&gt;
* This wiki is a part of my ([[User:Drorbn|Dror&#039;s]]) academic web page. All postings on it must be class-related (or related to one of the other projects I&#039;m involved with).&lt;br /&gt;
* You must login to edit. To get an account, email me your preferred login name, your real name and your email address if different from the address you are writing from.&lt;br /&gt;
* Criticism is fine, but no insults or foul language, please.&lt;br /&gt;
* I ([[User:Drorbn|Dror]]) will allow myself to exercise editorial control, when necessary.&lt;br /&gt;
* The titles of all pages related to this class should begin with &amp;quot;09-240/&amp;quot; or with &amp;quot;09-240-&amp;quot;, just like the title of this page.&lt;br /&gt;
Some further editing help is available at [[Help:Contents]].&lt;br /&gt;
&lt;br /&gt;
===Marking Scheme===&lt;br /&gt;
There will be one term test (25% of the total grade) and a final exam (50%), as well as about 9 homework assignments (25%).&lt;br /&gt;
&lt;br /&gt;
====The Term Test====&lt;br /&gt;
The term test will take place in class and on the first tutorial hour on Thursday October 22th, 1-3PM. A student who misses the term test without providing a valid reason (for example, a doctor’s note) within one week of the test will receive a mark of 0 on the term test. There will be no make-up term test. If a student misses the term test for a valid reason, the weight of the problem sets will increase to 35% and the weight of the final exam to 65%.&lt;br /&gt;
&lt;br /&gt;
====Homework====&lt;br /&gt;
Assignments will be posted on the course web page and distributed in class (usually on Tuesdays) approximately on the weeks shown in the class timeline. They will be due a week later at the tutorials (on Thursdays) and they will be (at least partially) marked by the TAs. All students (including those who join the course late) will receive a mark of 0 on each assignment not handed in; though in computing the homework grade, your worst two assignments will not count. I encourage you to discuss the assignments with other students or even browse the web, so long as you do at least some of the thinking on your own and you write up your own solutions. Remember that cheating is always possible and may increase your homework grade a bit. But it will hurt your appreciation of yourself, your knowledge and your exam grades a lot more.&lt;br /&gt;
&lt;br /&gt;
===Good Deeds===&lt;br /&gt;
Students will be able to earn up to 25 &amp;quot;good deeds&amp;quot; points throughout the year for doing services to the class as a whole. There is no pre-set system for awarding these points, but the following will definitely count:&lt;br /&gt;
* Drawing a beautiful picture to illustrate a point discussed in class and posting it on this site.&lt;br /&gt;
* Taking class notes in nice handwriting, scanning them and posting them here.&lt;br /&gt;
* Typing up or formatting somebody else&#039;s class notes, correcting them or expanding them in any way.&lt;br /&gt;
* Writing an essay on expanding on anything mentioned in class and posting it here; correcting or expanding somebody else&#039;s article.&lt;br /&gt;
* Doing anything on our [[09-240/To do]] list.&lt;br /&gt;
* Any other service to the class as a whole.&lt;br /&gt;
&lt;br /&gt;
Good deed points will count towards your final grade! If you got &amp;lt;math&amp;gt;n&amp;lt;/math&amp;gt; of those, they are solidly yours and the above formula for the final grade will only be applied to the remaining &amp;lt;math&amp;gt;100-n&amp;lt;/math&amp;gt; points. So if you got 25 good deed points (say) and your final grade is 80, I will report your grade as &amp;lt;math&amp;gt;25+80(100-25)/100=85&amp;lt;/math&amp;gt;. Yet you can get an overall 100 even without doing a single good deed.&lt;br /&gt;
&lt;br /&gt;
&#039;&#039;&#039;Important.&#039;&#039;&#039; For your good deeds to count, you &#039;&#039;&#039;must&#039;&#039;&#039; do them under your own name. So you must set up an account for yourself on this wiki and you must use it whenever you edit something. I will periodically check [[Special:Recentchanges|Recent changes]] to assign good deeds credits.&lt;br /&gt;
&lt;br /&gt;
===Class Photo===&lt;br /&gt;
To help me learn your names, I will take a class photo on Thursday of the third week of classes. I will post the picture on the class&#039; web site and you will be &#039;&#039;required&#039;&#039; to send me an email and identify yourself in the picture or to identify yourself on the [[09-240/Class Photo|Class Photo]] page of this wiki.&lt;br /&gt;
&lt;br /&gt;
===Accessibility Needs===&lt;br /&gt;
The University of Toronto is committed to accessibility. If you require accommodations for a disability, or have any accessibility concerns about the course, the classroom or course materials, please contact Accessibility Services as soon as possible: [mailto:disability.services@utoronto.ca disability.services@utoronto.ca] or http://studentlife.utoronto.ca/accessibility.&lt;br /&gt;
&lt;br /&gt;
===How to Succeed in this Class===&lt;br /&gt;
* &#039;&#039;&#039;Keep up!&#039;&#039;&#039; Don&#039;t fall behind on reading, listening, and doing assignments! University goes at a different pace than high school. New material is covered once and just once. There will be no going over the same thing again and again - if you fall behind, you stay behind. Unless you are an Einstein, there is &#039;&#039;no way&#039;&#039; to do well in this class merely by attending lectures - you &#039;&#039;&#039;must&#039;&#039;&#039; think about the material more than 3 or 5 hours a week if you want it to sink in. And if you are planning on not attending lectures, well, think again. Most people find it very hard to pace their own studies without a human contact; if you&#039;ll try, you are likely to discover the hard way that you belong to the majority.&lt;br /&gt;
* If in high school you were the best in your class in math, now remember that everybody around you was the same. You may find that what was enough then simply doesn&#039;t cut it any more. Try to catch that early in the year!&lt;br /&gt;
* Math is about &#039;&#039;&#039;understanding&#039;&#039;&#039;, not about memorizing. To understand is to internalize; it is to come to the point where whatever the professor does on the blackboard or whatever is printed in the books becomes &#039;&#039;&#039;yours&#039;&#039;&#039;; it is to come to the point where you appreciate why everything is done the way it is done, what does it mean, what are the reasons and motivations and what is it all good for. Don&#039;t settle for less!&lt;br /&gt;
* Keep asking yourself questions; many of them will be answered in class, but not all. Remember the old Chinese proverb:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&amp;lt;div style=&amp;quot;text-align: center; font-size: 18px&amp;quot;&amp;gt;&#039;&#039;&#039;&amp;quot;Teachers  open the door, but you must enter by yourself&amp;quot;&#039;&#039;&#039;&amp;lt;/div&amp;gt;&lt;br /&gt;
&amp;lt;div style=&amp;quot;text-align: center; font-size: 18px&amp;quot;&amp;gt;&#039;&#039;&#039;&amp;quot;师傅领进门,修行靠个人!&amp;quot;&#039;&#039;&#039;&amp;lt;/div&amp;gt;&lt;br /&gt;
&lt;br /&gt;
The saddest that can happen to you in this class is if you won&#039;t notice the door being opened.&lt;/div&gt;</summary>
		<author><name>Bofu2007</name></author>
	</entry>
	<entry>
		<id>https://drorbn.net/index.php?title=09-240/Classnotes_for_Tuesday_September_15&amp;diff=7752</id>
		<title>09-240/Classnotes for Tuesday September 15</title>
		<link rel="alternate" type="text/html" href="https://drorbn.net/index.php?title=09-240/Classnotes_for_Tuesday_September_15&amp;diff=7752"/>
		<updated>2009-09-16T04:26:37Z</updated>

		<summary type="html">&lt;p&gt;Bofu2007: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{09-240/Navigation}}&lt;br /&gt;
&lt;br /&gt;
&amp;lt;gallery&amp;gt;&lt;br /&gt;
Image:09-240 Classnotes for Tuesday September 15 2009 page 1.jpg|Page 1&lt;br /&gt;
Image:09-240 Classnotes for Tuesday September 15 2009 page 2.jpg|Page 2&lt;br /&gt;
Image:09-240 Classnotes for Tuesday September 15 2009 page 3.jpg|Page 3&lt;br /&gt;
Image:09-240 Classnotes for Tuesday September 15 2009 page 4.jpg|Page 4&lt;br /&gt;
Image:09-240 Classnotes for Tuesday September 15 2009 page 5.jpg|Page 5&lt;br /&gt;
&amp;lt;/gallery&amp;gt;&lt;br /&gt;
&lt;br /&gt;
The real numbers A set &amp;lt;math&amp;gt;\mathbb R&amp;lt;/math&amp;gt; with two binary operators and two special elements &amp;lt;math&amp;gt;0, 1 \in \mathbb R&amp;lt;/math&amp;gt; s.t.&lt;br /&gt;
&lt;br /&gt;
: &amp;lt;math&amp;gt;F1.\quad \forall a, b \in \mathbb R, a + b = b + a \mbox{ and } a \cdot b = b \cdot a&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;F2.\quad \forall a, b, c, (a + b) + c = a + (b + c) \mbox{ and } (a \cdot b) \cdot c = a \cdot (b \cdot c)&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;\mbox{(So for any real numbers } a_1, a_2, ..., a_n, \mbox{ one can sum them in any order and achieve the same result.}&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;F3.\quad \forall a, a + 0 = a \mbox{ and } a \cdot 0 = 0 \mbox{ and } a \cdot 1 = a&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;F4.\quad \forall a, \exists b, a + b = 0 \mbox{ and } \forall a \ne 0, \exists b, a \cdot b = 1&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;\mbox{So } a + (-a) = 0 \mbox{ and } a \cdot a^{-1} = 1&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;\mbox{(So } (a + b) \cdot (a - b) = a^2 - b^2)&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;\forall a, \exists x, x \cdot x = a \mbox{ or } a + x \cdot x = 0&amp;lt;/math&amp;gt;&lt;br /&gt;
: Note: &#039;&#039;&#039;or&#039;&#039;&#039; means &#039;&#039;&#039;inclusive or&#039;&#039;&#039; in math.&lt;br /&gt;
: &amp;lt;math&amp;gt;F5.\quad (a + b) \cdot c = a \cdot c + b \cdot c&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;u&amp;gt;Definition&amp;lt;/u&amp;gt;: A &#039;&#039;&#039;field&#039;&#039;&#039; is a set &#039;&#039;F&#039;&#039; with two binary operators &amp;lt;math&amp;gt;\,\!+&amp;lt;/math&amp;gt;: &#039;&#039;F&#039;&#039;×&#039;&#039;F&#039;&#039; → &#039;&#039;F&#039;&#039;, &amp;lt;math&amp;gt;\times\,\!&amp;lt;/math&amp;gt;: &#039;&#039;F&#039;&#039;×&#039;&#039;F&#039;&#039; → &#039;&#039;F&#039;&#039; and two elements &amp;lt;math&amp;gt;0, 1 \in \mathbb R&amp;lt;/math&amp;gt; s.t.&lt;br /&gt;
: &amp;lt;math&amp;gt;F1\quad \mbox{Commutativity } a + b = b + a \mbox{ and } a \cdot b = b \cdot a \forall a, b \in F&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;F2\quad \mbox{Associativity } (a + b) + c = a + (b + c) \mbox{ and } (a \cdot b) \cdot c = a \cdot (b \cdot c)&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;F3\quad a + 0 = a, a \cdot 1 = a&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;F4\quad \forall a, \exists b, a + b = 0 \mbox{ and } \forall a \ne 0, \exists b, a \cdot b = 1&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;F5\quad \mbox{Distributivity } (a + b) \cdot c = a \cdot c + b \cdot c&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
== Examples ==&lt;br /&gt;
&lt;br /&gt;
# &amp;lt;math&amp;gt;F = \mathbb R&amp;lt;/math&amp;gt;&lt;br /&gt;
# &amp;lt;math&amp;gt;F = \mathbb Q&amp;lt;/math&amp;gt;&lt;br /&gt;
# &amp;lt;math&amp;gt;\mathbb C = \{ a + bi : a, b \in \mathbb R \}&amp;lt;/math&amp;gt;&lt;br /&gt;
#: &amp;lt;math&amp;gt;i = \sqrt{-1}&amp;lt;/math&amp;gt;&lt;br /&gt;
#: &amp;lt;math&amp;gt;\,\!(a + bi) + (c + di) = (a + c) + (b + d)i&amp;lt;/math&amp;gt;&lt;br /&gt;
#: &amp;lt;math&amp;gt;\,\!0 = 0 + 0i, 1 = 1 + 0i&amp;lt;/math&amp;gt;&lt;br /&gt;
# &amp;lt;math&amp;gt;\,\!F_2 = \{ 0, 1 \}&amp;lt;/math&amp;gt;&lt;br /&gt;
# &amp;lt;math&amp;gt;\,\!F_7 = \{ 0, 1,2,3,4,5,6 \}&amp;lt;/math&amp;gt;&lt;br /&gt;
# &amp;lt;math&amp;gt;\,\!F_6 = \{ 0, 1,2,3,4,5 \}&amp;lt;/math&amp;gt; is not a field because not every element has a multiplicative inverse.&lt;br /&gt;
#: Let &amp;lt;math&amp;gt;a = 2.&amp;lt;/math&amp;gt;&lt;br /&gt;
#: Then &amp;lt;math&amp;gt;a \cdot 0 = 0, a \cdot 1 = 2, a \cdot 3 = 0, a \cdot 4 = 2, a \cdot 5 = 4&amp;lt;/math&amp;gt;&lt;br /&gt;
#: Therefore F4 fails; there is &#039;&#039;&#039;no&#039;&#039;&#039; number &#039;&#039;b&#039;&#039; in &#039;&#039;F&#039;&#039;&amp;lt;sub&amp;gt;6&amp;lt;/sub&amp;gt; s.t. &#039;&#039;a · b&#039;&#039; = 1&lt;br /&gt;
&lt;br /&gt;
{|&lt;br /&gt;
|&lt;br /&gt;
{| border=&amp;quot;1&amp;quot; cellspacing=&amp;quot;0&amp;quot;&lt;br /&gt;
|+ Ex. 4&lt;br /&gt;
|-&lt;br /&gt;
! + !! 0 !! 1&lt;br /&gt;
|-&lt;br /&gt;
! 0&lt;br /&gt;
| 0 || 1&lt;br /&gt;
|-&lt;br /&gt;
! 1&lt;br /&gt;
| 1 || 0&lt;br /&gt;
|-&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
|&lt;br /&gt;
{| border=&amp;quot;1&amp;quot; cellspacing=&amp;quot;0&amp;quot;&lt;br /&gt;
|+ Ex. 4&lt;br /&gt;
|-&lt;br /&gt;
! × !! 0 !! 1&lt;br /&gt;
|-&lt;br /&gt;
! 0&lt;br /&gt;
| 0 || 0&lt;br /&gt;
|-&lt;br /&gt;
! 1&lt;br /&gt;
| 0 || 1&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
|&lt;br /&gt;
{| border=&amp;quot;1&amp;quot; cellspacing=&amp;quot;0&amp;quot;&lt;br /&gt;
|+ Ex. 5&lt;br /&gt;
|-&lt;br /&gt;
! + !! 0 !! 1 !! 2 !! 3 !! 4 !! 5 !! 6&lt;br /&gt;
|-&lt;br /&gt;
! 0&lt;br /&gt;
| 0 || 1 || 2 || 3 || 4 || 5 || 6&lt;br /&gt;
|-&lt;br /&gt;
! 1&lt;br /&gt;
| 1 || 2 || 3 || 4 || 5 || 6 || 0&lt;br /&gt;
|-&lt;br /&gt;
! 2&lt;br /&gt;
| 2 || 3 || 4 || 5 || 6 || 0 || 1&lt;br /&gt;
|-&lt;br /&gt;
! 3&lt;br /&gt;
| 3 || 4 || 5 || 6 || 0 || 1 || 2&lt;br /&gt;
|-&lt;br /&gt;
! 4&lt;br /&gt;
| 4 || 5 || 6 || 0 || 1 || 2 || 3&lt;br /&gt;
|-&lt;br /&gt;
! 5&lt;br /&gt;
| 5 || 6 || 0 || 1 || 2 || 3 || 4&lt;br /&gt;
|-&lt;br /&gt;
! 6&lt;br /&gt;
| 6 || 0 || 1 || 2 || 3 || 4 || 5&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
|&lt;br /&gt;
{|border=&amp;quot;1&amp;quot; cellspacing=&amp;quot;0&amp;quot;&lt;br /&gt;
|+ Ex. 5&lt;br /&gt;
|-&lt;br /&gt;
! × !! 0 !! 1 !! 2 !! 3 !! 4 !! 5 !! 6&lt;br /&gt;
|-&lt;br /&gt;
! 0&lt;br /&gt;
| 0 || 0 || 0 || 0 || 0 || 0 || 0&lt;br /&gt;
|-&lt;br /&gt;
! 1&lt;br /&gt;
| 0 || 1 || 2 || 3 || 4 || 5 || 0&lt;br /&gt;
|-&lt;br /&gt;
! 2&lt;br /&gt;
| 0 || 2 || 4 || 6 || 1 || 3 || 1&lt;br /&gt;
|-&lt;br /&gt;
! 3&lt;br /&gt;
| 0 || 3 || 6 || 2 || 5 || 1 || 2&lt;br /&gt;
|-&lt;br /&gt;
! 4&lt;br /&gt;
| 0 || 4 || 1 || 5 || 2 || 6 || 3&lt;br /&gt;
|-&lt;br /&gt;
! 5&lt;br /&gt;
| 0 || 5 || 3 || 1 || 6 || 4 || 4&lt;br /&gt;
|-&lt;br /&gt;
! 6&lt;br /&gt;
| 0 || 6 || 5 || 4 || 3 || 2 || 5&lt;br /&gt;
|}&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
&#039;&#039;&#039;Theorem&#039;&#039;&#039;: &amp;lt;math&amp;gt;\,\!F_P &amp;lt;/math&amp;gt; for &amp;lt;math&amp;gt;p&amp;gt;1&amp;lt;/math&amp;gt; is a field &#039;&#039;iff&#039;&#039; &amp;lt;small&amp;gt;([http://en.wikipedia.org/wiki/If_and_only_if if and only if])&amp;lt;/small&amp;gt; &amp;lt;math&amp;gt;p&amp;lt;/math&amp;gt; is a prime number&lt;br /&gt;
&lt;br /&gt;
== Tedious Theorem ==&lt;br /&gt;
# &amp;lt;math&amp;gt;a + b = c + d \Rightarrow a = c &amp;lt;/math&amp;gt; &amp;quot;cancellation property&amp;quot;&lt;br /&gt;
#: Proof:&lt;br /&gt;
#: By F4, &amp;lt;math&amp;gt;\exists d \mbox{ s.t. } b + d = 0&amp;lt;/math&amp;gt;&lt;br /&gt;
#: &amp;lt;math&amp;gt;\,\! (a + b) + d = (c + b) + d&amp;lt;/math&amp;gt;&lt;br /&gt;
#: &amp;lt;math&amp;gt;\Rightarrow a + (b + d) = c + (b + d)&amp;lt;/math&amp;gt; by F2&lt;br /&gt;
#: &amp;lt;math&amp;gt;\Rightarrow a + 0 = c + 0&amp;lt;/math&amp;gt; by choice of &#039;&#039;d&#039;&#039;&lt;br /&gt;
#: &amp;lt;math&amp;gt;\Rightarrow a = c&amp;lt;/math&amp;gt; by F3&lt;br /&gt;
# &amp;lt;math&amp;gt; a \cdot b = c \cdot b , (b \ne 0) \Rightarrow a = c &amp;lt;/math&amp;gt; &lt;br /&gt;
# &amp;lt;math&amp;gt;a + O&#039; = a \Rightarrow O&#039; = 0&amp;lt;/math&amp;gt;&lt;br /&gt;
#: Proof:&lt;br /&gt;
#: &amp;lt;math&amp;gt;\,\! a + O&#039; = a&amp;lt;/math&amp;gt;&lt;br /&gt;
#: &amp;lt;math&amp;gt;\Rightarrow a + O&#039; = a + 0&amp;lt;/math&amp;gt; by F3&lt;br /&gt;
#: &amp;lt;math&amp;gt;\Rightarrow O&#039; = 0&amp;lt;/math&amp;gt; by adding the additive inverse of &#039;&#039;a&#039;&#039; to both sides&lt;br /&gt;
# &amp;lt;math&amp;gt;a \cdot l&#039; = a, a \ne 0 \Rightarrow l&#039; = 1&amp;lt;/math&amp;gt;&lt;br /&gt;
# &amp;lt;math&amp;gt;a + b = 0 = a + b&#039; \Rightarrow b = b&#039;&amp;lt;/math&amp;gt;&lt;br /&gt;
# &amp;lt;math&amp;gt;a \cdot b = 1 = a \cdot b&#039; \Rightarrow b = b&#039; = a^{-1}&amp;lt;/math&amp;gt;&lt;br /&gt;
#: &amp;lt;math&amp;gt;\,\! \mbox{Aside: } a - b = a + (-b)&amp;lt;/math&amp;gt;&lt;br /&gt;
#: &amp;lt;math&amp;gt;\frac ab = a \cdot b^{-1}&amp;lt;/math&amp;gt;&lt;br /&gt;
# &amp;lt;math&amp;gt;\,\! -(-a) = a, (a^{-1})^{-1}&amp;lt;/math&amp;gt;&lt;br /&gt;
# &amp;lt;math&amp;gt;a \cdot 0 = 0&amp;lt;/math&amp;gt;&lt;br /&gt;
#: Proof:&lt;br /&gt;
#: &amp;lt;math&amp;gt;a \cdot 0 = a(0 + 0)&amp;lt;/math&amp;gt; by F3&lt;br /&gt;
#: &amp;lt;math&amp;gt;= a \cdot 0 + a \cdot 0&amp;lt;/math&amp;gt; by F5&lt;br /&gt;
#: &amp;lt;math&amp;gt;= 0 = a \cdot 0&amp;lt;/math&amp;gt;&lt;br /&gt;
# &amp;lt;math&amp;gt;\forall b, 0 \cdot b \ne 1&amp;lt;/math&amp;gt;&lt;br /&gt;
#: So there is no 0&amp;lt;sup&amp;gt;&amp;amp;minus;1&amp;lt;/sup&amp;gt;&lt;br /&gt;
# &amp;lt;math&amp;gt;(-a) \cdot b = a \cdot (-b) = -(a \cdot b)&amp;lt;/math&amp;gt;&lt;br /&gt;
# &amp;lt;math&amp;gt;(-a) \cdot (-b) = a \cdot b&amp;lt;/math&amp;gt;&lt;br /&gt;
# (Bonus) &amp;lt;math&amp;gt;\,\! (a + b)(a - b) = a^2 - b^2&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
== Quotation of the Day ==&lt;br /&gt;
......&lt;/div&gt;</summary>
		<author><name>Bofu2007</name></author>
	</entry>
	<entry>
		<id>https://drorbn.net/index.php?title=Template:09-240/Navigation&amp;diff=7751</id>
		<title>Template:09-240/Navigation</title>
		<link rel="alternate" type="text/html" href="https://drorbn.net/index.php?title=Template:09-240/Navigation&amp;diff=7751"/>
		<updated>2009-09-16T04:23:54Z</updated>

		<summary type="html">&lt;p&gt;Bofu2007: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{| cellpadding=&amp;quot;0&amp;quot; cellspacing=&amp;quot;0&amp;quot; style=&amp;quot;clear: right; float: right&amp;quot;&lt;br /&gt;
|- align=right&lt;br /&gt;
|&amp;lt;div class=&amp;quot;NavFrame&amp;quot;&amp;gt;&amp;lt;div class=&amp;quot;NavHead&amp;quot;&amp;gt;[[09-240]]/[[Template:09-240/Navigation|Navigation Panel]]&amp;amp;nbsp;&amp;amp;nbsp;&amp;lt;/div&amp;gt;&lt;br /&gt;
&amp;lt;div class=&amp;quot;NavContent&amp;quot;&amp;gt;&lt;br /&gt;
{| border=&amp;quot;1px&amp;quot; cellpadding=&amp;quot;1&amp;quot; cellspacing=&amp;quot;0&amp;quot; width=&amp;quot;220&amp;quot; style=&amp;quot;margin: 0 0 1em 0.5em; font-size: small&amp;quot;&lt;br /&gt;
|-&lt;br /&gt;
!#&lt;br /&gt;
!Week of...&lt;br /&gt;
!Notes and Links&lt;br /&gt;
|-&lt;br /&gt;
|align=center|1&lt;br /&gt;
|Sep 7&lt;br /&gt;
|&amp;lt;s&amp;gt;Tue&amp;lt;/s&amp;gt;, [[09-240/About This Class|About]], [[09-240/Classnotes for Thursday September 10|Thu]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|2&lt;br /&gt;
|Sep 14&lt;br /&gt;
|[[09-240:HW1|HW1]], [[09-240/Classnotes for Tuesday September 15|Tue]], [[09-240:HW1 Solution|HW1 Solution]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|3&lt;br /&gt;
|Sep 21&lt;br /&gt;
|[[09-240:HW2|HW2]], [[09-240/Class Photo|Photo]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|4&lt;br /&gt;
|Sep 28&lt;br /&gt;
|[[09-240:HW3|HW3]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|5&lt;br /&gt;
|Oct 5&lt;br /&gt;
|[[09-240:HW4|HW4]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|6&lt;br /&gt;
|Oct 12&lt;br /&gt;
|&lt;br /&gt;
|-&lt;br /&gt;
|align=center|7&lt;br /&gt;
|Oct 19&lt;br /&gt;
|[[09-240:HW5|HW5]], [[09-240/Term Test|Term Test on Thu]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|8&lt;br /&gt;
|Oct 26&lt;br /&gt;
|[[09-240:HW6|HW6]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|9&lt;br /&gt;
|Nov 2&lt;br /&gt;
|&lt;br /&gt;
|-&lt;br /&gt;
|align=center|10&lt;br /&gt;
|Nov 9&lt;br /&gt;
|[[09-240:HW7|HW7]], &amp;lt;s&amp;gt;Thu&amp;lt;/s&amp;gt;&lt;br /&gt;
|-&lt;br /&gt;
|align=center|11&lt;br /&gt;
|Nov 16&lt;br /&gt;
|[[09-240:HW8|HW8]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|12&lt;br /&gt;
|Nov 23&lt;br /&gt;
|[[09-240:HW9|HW9]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|13&lt;br /&gt;
|Nov 30&lt;br /&gt;
|[[09-240/On The Final Exam|On the final]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|F&lt;br /&gt;
|&lt;br /&gt;
|[[09-240/The Final Exam|Final]]&lt;br /&gt;
|-&lt;br /&gt;
|colspan=3 align=center|[[09-240/Register of Good Deeds|Register of Good Deeds]]&lt;br /&gt;
|-&lt;br /&gt;
|colspan=3 align=center|[[Image:09-240-ClassPhoto.jpg|180px]]&amp;lt;br&amp;gt;[[09-240/Class Photo|Add your name / see who&#039;s in!]]&lt;br /&gt;
|-&lt;br /&gt;
|colspan=3 align=center|[[09-240/Lecture Notes|Lecture Notes]]&lt;br /&gt;
|}&lt;br /&gt;
&amp;lt;/div&amp;gt;&amp;lt;/div&amp;gt;&lt;br /&gt;
|}&lt;/div&gt;</summary>
		<author><name>Bofu2007</name></author>
	</entry>
	<entry>
		<id>https://drorbn.net/index.php?title=09-240/Classnotes_for_Tuesday_September_15&amp;diff=7727</id>
		<title>09-240/Classnotes for Tuesday September 15</title>
		<link rel="alternate" type="text/html" href="https://drorbn.net/index.php?title=09-240/Classnotes_for_Tuesday_September_15&amp;diff=7727"/>
		<updated>2009-09-16T01:25:46Z</updated>

		<summary type="html">&lt;p&gt;Bofu2007: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;&amp;lt;math&amp;gt;Insert formula here&amp;lt;/math&amp;gt;&amp;lt;math&amp;gt;Insert formula here&amp;lt;/math&amp;gt;[[Image:Classnotes For Tuesday, September 15.jpg]]&lt;br /&gt;
[[yangjiay:09-240 Classnotes for Tuesday September 15 2009 page 5.jpg]]&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
The real numbers A set &amp;lt;math&amp;gt;\mathbb R&amp;lt;/math&amp;gt; with two binary operators and two special elements &amp;lt;math&amp;gt;0, 1 \in \mathbb R&amp;lt;/math&amp;gt; s.t.&lt;br /&gt;
&lt;br /&gt;
: &amp;lt;math&amp;gt;F1.\quad \forall a, b \in \mathbb R, a + b = b + a \mbox{ and } a \cdot b = b \cdot a&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;F2.\quad \forall a, b, c, (a + b) + c = a + (b + c) \mbox{ and } (a \cdot b) \cdot c = a \cdot (b \cdot c)&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;\mbox{(So for any real numbers } a_1, a_2, ..., a_n, \mbox{ one can sum them in any order and achieve the same result.}&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;F3.\quad \forall a, a + 0 = a \mbox{ and } a \cdot 0 = 0 \mbox{ and } a \cdot 1 = a&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;F4.\quad \forall a, \exists b, a + b = 0 \mbox{ and } \forall a \ne 0, \exists b, a \cdot b = 1&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;\mbox{So } a + (-a) = 0 \mbox{ and } a \cdot a^{-1} = 1&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;\mbox{(So } (a + b) \cdot (a - b) = a^2 - b^2)&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;\forall a, \exists x, x \cdot x = a \mbox{ or } a + x \cdot x = 0&amp;lt;/math&amp;gt;&lt;br /&gt;
: Note: &#039;&#039;&#039;or&#039;&#039;&#039; means &#039;&#039;&#039;inclusive or&#039;&#039;&#039; in math.&lt;br /&gt;
: &amp;lt;math&amp;gt;F5.\quad (a + b) \cdot c = a \cdot c + b \cdot c&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;u&amp;gt;Definition&amp;lt;/u&amp;gt;: A &#039;&#039;&#039;field&#039;&#039;&#039; is a set &#039;&#039;F&#039;&#039; with two binary operators &amp;lt;math&amp;gt;\,\!+&amp;lt;/math&amp;gt;: &#039;&#039;F&#039;&#039;×&#039;&#039;F&#039;&#039; → &#039;&#039;F&#039;&#039;, &amp;lt;math&amp;gt;\times\,\!&amp;lt;/math&amp;gt;: &#039;&#039;F&#039;&#039;×&#039;&#039;F&#039;&#039; → &#039;&#039;F&#039;&#039; and two elements &amp;lt;math&amp;gt;0, 1 \in \mathbb R&amp;lt;/math&amp;gt; s.t.&lt;br /&gt;
: &amp;lt;math&amp;gt;F1\quad \mbox{Commutativity } a + b = b + a \mbox{ and } a \cdot b = b \cdot a \forall a, b \in F&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;F2\quad \mbox{Associativity } (a + b) + c = a + (b + c) \mbox{ and } (a \cdot b) \cdot c = a \cdot (b \cdot c)&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;F3\quad a + 0 = a, a \cdot 1 = a&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;F4\quad \forall a, \exists b, a + b = 0 \mbox{ and } \forall a \ne 0, \exists b, a \cdot b = 1&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;F5\quad \mbox{Distributivity } (a + b) \cdot c = a \cdot c + b \cdot c&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
== Examples ==&lt;br /&gt;
&lt;br /&gt;
# &amp;lt;math&amp;gt;F = \mathbb R&amp;lt;/math&amp;gt;&lt;br /&gt;
# &amp;lt;math&amp;gt;F = \mathbb Q&amp;lt;/math&amp;gt;&lt;br /&gt;
# &amp;lt;math&amp;gt;\mathbb C = \{ a + bi : a, b \in \mathbb R \}&amp;lt;/math&amp;gt;&lt;br /&gt;
#: &amp;lt;math&amp;gt;i = \sqrt{-1}&amp;lt;/math&amp;gt;&lt;br /&gt;
#: &amp;lt;math&amp;gt;\,\!(a + bi) + (c + di) = (a + c) + (b + d)i&amp;lt;/math&amp;gt;&lt;br /&gt;
#: &amp;lt;math&amp;gt;\,\!0 = 0 + 0i, 1 = 1 + 0i&amp;lt;/math&amp;gt;&lt;br /&gt;
# &amp;lt;math&amp;gt;\,\!F_2 = \{ 0, 1 \}&amp;lt;/math&amp;gt;&lt;br /&gt;
# &amp;lt;math&amp;gt;\,\!F_7 = \{ 0, 1,2,3,4,5,6 \}&amp;lt;/math&amp;gt;&lt;br /&gt;
# &amp;lt;math&amp;gt;\,\!F_6 = \{ 0, 1,2,3,4,5 \}&amp;lt;/math&amp;gt; is not a field (counterexample) &lt;br /&gt;
&#039;&#039;&#039;Theorem&#039;&#039;&#039;: &amp;lt;math&amp;gt;\,\!F_P &amp;lt;/math&amp;gt; for &amp;lt;math&amp;gt;p&amp;gt;1&amp;lt;/math&amp;gt; is a field &#039;&#039;&#039;IFF&#039;&#039;&#039; &amp;lt;math&amp;gt;p&amp;lt;/math&amp;gt; is a prime number&lt;br /&gt;
&lt;br /&gt;
== Tedious Theorem ==&lt;br /&gt;
# &amp;lt;math&amp;gt;a + b = c + d \Rightarrow a = c &amp;lt;/math&amp;gt; &amp;quot;cancellation property&amp;quot;&lt;br /&gt;
# &amp;lt;math&amp;gt; a \cdot b = c \cdot b , (b \ne 0) \Rightarrow a = c &amp;lt;/math&amp;gt; &lt;br /&gt;
&lt;br /&gt;
...&lt;/div&gt;</summary>
		<author><name>Bofu2007</name></author>
	</entry>
	<entry>
		<id>https://drorbn.net/index.php?title=09-240/Classnotes_for_Tuesday_September_15&amp;diff=7726</id>
		<title>09-240/Classnotes for Tuesday September 15</title>
		<link rel="alternate" type="text/html" href="https://drorbn.net/index.php?title=09-240/Classnotes_for_Tuesday_September_15&amp;diff=7726"/>
		<updated>2009-09-16T01:25:15Z</updated>

		<summary type="html">&lt;p&gt;Bofu2007: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;&amp;lt;math&amp;gt;Insert formula here&amp;lt;/math&amp;gt;&amp;lt;math&amp;gt;Insert formula here&amp;lt;/math&amp;gt;[[Image:Classnotes For Tuesday, September 15.jpg]]&lt;br /&gt;
[[yangjiay:09-240 Classnotes for Tuesday September 15 2009 page 5.jpg]]&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
The real numbers A set &amp;lt;math&amp;gt;\mathbb R&amp;lt;/math&amp;gt; with two binary operators and two special elements &amp;lt;math&amp;gt;0, 1 \in \mathbb R&amp;lt;/math&amp;gt; s.t.&lt;br /&gt;
&lt;br /&gt;
: &amp;lt;math&amp;gt;F1.\quad \forall a, b \in \mathbb R, a + b = b + a \mbox{ and } a \cdot b = b \cdot a&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;F2.\quad \forall a, b, c, (a + b) + c = a + (b + c) \mbox{ and } (a \cdot b) \cdot c = a \cdot (b \cdot c)&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;\mbox{(So for any real numbers } a_1, a_2, ..., a_n, \mbox{ one can sum them in any order and achieve the same result.}&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;F3.\quad \forall a, a + 0 = a \mbox{ and } a \cdot 0 = 0 \mbox{ and } a \cdot 1 = a&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;F4.\quad \forall a, \exists b, a + b = 0 \mbox{ and } \forall a \ne 0, \exists b, a \cdot b = 1&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;\mbox{So } a + (-a) = 0 \mbox{ and } a \cdot a^{-1} = 1&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;\mbox{(So } (a + b) \cdot (a - b) = a^2 - b^2)&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;\forall a, \exists x, x \cdot x = a \mbox{ or } a + x \cdot x = 0&amp;lt;/math&amp;gt;&lt;br /&gt;
: Note: &#039;&#039;&#039;or&#039;&#039;&#039; means &#039;&#039;&#039;inclusive or&#039;&#039;&#039; in math.&lt;br /&gt;
: &amp;lt;math&amp;gt;F5.\quad (a + b) \cdot c = a \cdot c + b \cdot c&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;u&amp;gt;Definition&amp;lt;/u&amp;gt;: A &#039;&#039;&#039;field&#039;&#039;&#039; is a set &#039;&#039;F&#039;&#039; with two binary operators &amp;lt;math&amp;gt;\,\!+&amp;lt;/math&amp;gt;: &#039;&#039;F&#039;&#039;×&#039;&#039;F&#039;&#039; → &#039;&#039;F&#039;&#039;, &amp;lt;math&amp;gt;\times\,\!&amp;lt;/math&amp;gt;: &#039;&#039;F&#039;&#039;×&#039;&#039;F&#039;&#039; → &#039;&#039;F&#039;&#039; and two elements &amp;lt;math&amp;gt;0, 1 \in \mathbb R&amp;lt;/math&amp;gt; s.t.&lt;br /&gt;
: &amp;lt;math&amp;gt;F1\quad \mbox{Commutativity } a + b = b + a \mbox{ and } a \cdot b = b \cdot a \forall a, b \in F&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;F2\quad \mbox{Associativity } (a + b) + c = a + (b + c) \mbox{ and } (a \cdot b) \cdot c = a \cdot (b \cdot c)&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;F3\quad a + 0 = a, a \cdot 1 = a&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;F4\quad \forall a, \exists b, a + b = 0 \mbox{ and } \forall a \ne 0, \exists b, a \cdot b = 1&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;F5\quad \mbox{Distributivity } (a + b) \cdot c = a \cdot c + b \cdot c&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
== Examples ==&lt;br /&gt;
&lt;br /&gt;
# &amp;lt;math&amp;gt;F = \mathbb R&amp;lt;/math&amp;gt;&lt;br /&gt;
# &amp;lt;math&amp;gt;F = \mathbb Q&amp;lt;/math&amp;gt;&lt;br /&gt;
# &amp;lt;math&amp;gt;\mathbb C = \{ a + bi : a, b \in \mathbb R \}&amp;lt;/math&amp;gt;&lt;br /&gt;
#: &amp;lt;math&amp;gt;i = \sqrt{-1}&amp;lt;/math&amp;gt;&lt;br /&gt;
#: &amp;lt;math&amp;gt;\,\!(a + bi) + (c + di) = (a + c) + (b + d)i&amp;lt;/math&amp;gt;&lt;br /&gt;
#: &amp;lt;math&amp;gt;\,\!0 = 0 + 0i, 1 = 1 + 0i&amp;lt;/math&amp;gt;&lt;br /&gt;
# &amp;lt;math&amp;gt;\,\!F_2 = \{ 0, 1 \}&amp;lt;/math&amp;gt;&lt;br /&gt;
# &amp;lt;math&amp;gt;\,\!F_7 = \{ 0, 1,2,3,4,5,6 \}&amp;lt;/math&amp;gt;&lt;br /&gt;
# &amp;lt;math&amp;gt;\,\!F_6 = \{ 0, 1,2,3,4,5 \}&amp;lt;/math&amp;gt; is not a field (counterexample) &lt;br /&gt;
&#039;&#039;&#039;Theorem&#039;&#039;&#039;: &amp;lt;math&amp;gt;\,\!F_P &amp;lt;/math&amp;gt; for &amp;lt;math&amp;gt;p&amp;gt;1&amp;lt;/math&amp;gt; is a field &#039;&#039;&#039;IFF&#039;&#039;&#039; &amp;lt;math&amp;gt;p&amp;lt;/math&amp;gt; is a prime number&lt;br /&gt;
&lt;br /&gt;
== Tedious Theorem ==&lt;br /&gt;
# &amp;lt;math&amp;gt;a + b = c + d \Rightarrow a = c &amp;lt;/math&amp;gt; &amp;quot;cancellation property&amp;quot;&lt;br /&gt;
# &amp;lt;math&amp;gt; a \cdot b = c \cdot b , (b \ne 0) \Rightarrow a = c &amp;lt;/math&amp;gt; &lt;br /&gt;
# &lt;br /&gt;
...&lt;/div&gt;</summary>
		<author><name>Bofu2007</name></author>
	</entry>
	<entry>
		<id>https://drorbn.net/index.php?title=09-240/Classnotes_for_Tuesday_September_15&amp;diff=7725</id>
		<title>09-240/Classnotes for Tuesday September 15</title>
		<link rel="alternate" type="text/html" href="https://drorbn.net/index.php?title=09-240/Classnotes_for_Tuesday_September_15&amp;diff=7725"/>
		<updated>2009-09-16T01:10:07Z</updated>

		<summary type="html">&lt;p&gt;Bofu2007: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;&amp;lt;math&amp;gt;Insert formula here&amp;lt;/math&amp;gt;&amp;lt;math&amp;gt;Insert formula here&amp;lt;/math&amp;gt;[[Image:Classnotes For Tuesday, September 15.jpg]]&lt;br /&gt;
[[yangjiay:09-240 Classnotes for Tuesday September 15 2009 page 5.jpg]]&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
The real numbers A set &amp;lt;math&amp;gt;\mathbb R&amp;lt;/math&amp;gt; with two binary operators and two special elements &amp;lt;math&amp;gt;0, 1 \in \mathbb R&amp;lt;/math&amp;gt; s.t.&lt;br /&gt;
&lt;br /&gt;
: &amp;lt;math&amp;gt;F1.\quad \forall a, b \in \mathbb R, a + b = b + a \mbox{ and } a \cdot b = b \cdot a&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;F2.\quad \forall a, b, c, (a + b) + c = a + (b + c) \mbox{ and } (a \cdot b) \cdot c = a \cdot (b \cdot c)&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;\mbox{(So for any real numbers } a_1, a_2, ..., a_n, \mbox{ one can sum them in any order and achieve the same result.}&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;F3.\quad \forall a, a + 0 = a \mbox{ and } a \cdot 0 = 0 \mbox{ and } a \cdot 1 = a&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;F4.\quad \forall a, \exists b, a + b = 0 \mbox{ and } \forall a \ne 0, \exists b, a \cdot b = 1&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;\mbox{So } a + (-a) = 0 \mbox{ and } a \cdot a^{-1} = 1&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;\mbox{(So } (a + b) \cdot (a - b) = a^2 - b^2)&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;\forall a, \exists x, x \cdot x = a \mbox{ or } a + x \cdot x = 0&amp;lt;/math&amp;gt;&lt;br /&gt;
: Note: &#039;&#039;&#039;or&#039;&#039;&#039; means &#039;&#039;&#039;inclusive or&#039;&#039;&#039; in math.&lt;br /&gt;
: &amp;lt;math&amp;gt;F5.\quad (a + b) \cdot c = a \cdot c + b \cdot c&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;u&amp;gt;Definition&amp;lt;/u&amp;gt;: A &#039;&#039;&#039;field&#039;&#039;&#039; is a set &#039;&#039;F&#039;&#039; with two binary operators &amp;lt;math&amp;gt;\,\!+&amp;lt;/math&amp;gt;: &#039;&#039;F&#039;&#039;×&#039;&#039;F&#039;&#039; → &#039;&#039;F&#039;&#039;, &amp;lt;math&amp;gt;\times\,\!&amp;lt;/math&amp;gt;: &#039;&#039;F&#039;&#039;×&#039;&#039;F&#039;&#039; → &#039;&#039;F&#039;&#039; and two elements &amp;lt;math&amp;gt;0, 1 \in \mathbb R&amp;lt;/math&amp;gt; s.t.&lt;br /&gt;
: &amp;lt;math&amp;gt;F1\quad \mbox{Commutativity } a + b = b + a \mbox{ and } a \cdot b = b \cdot a \forall a, b \in F&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;F2\quad \mbox{Associativity } (a + b) + c = a + (b + c) \mbox{ and } (a \cdot b) \cdot c = a \cdot (b \cdot c)&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;F3\quad a + 0 = a, a \cdot 1 = a&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;F4\quad \forall a, \exists b, a + b = 0 \mbox{ and } \forall a \ne 0, \exists b, a \cdot b = 1&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;F5\quad \mbox{Distributivity } (a + b) \cdot c = a \cdot c + b \cdot c&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
== Examples ==&lt;br /&gt;
&lt;br /&gt;
# &amp;lt;math&amp;gt;F = \mathbb R&amp;lt;/math&amp;gt;&lt;br /&gt;
# &amp;lt;math&amp;gt;F = \mathbb Q&amp;lt;/math&amp;gt;&lt;br /&gt;
# &amp;lt;math&amp;gt;\mathbb C = \{ a + bi : a, b \in \mathbb R \}&amp;lt;/math&amp;gt;&lt;br /&gt;
#: &amp;lt;math&amp;gt;i = \sqrt{-1}&amp;lt;/math&amp;gt;&lt;br /&gt;
#: &amp;lt;math&amp;gt;\,\!(a + bi) + (c + di) = (a + c) + (b + d)i&amp;lt;/math&amp;gt;&lt;br /&gt;
#: &amp;lt;math&amp;gt;\,\!0 = 0 + 0i, 1 = 1 + 0i&amp;lt;/math&amp;gt;&lt;br /&gt;
# &amp;lt;math&amp;gt;\,\!F_2 = \{ 0, 1 \}&amp;lt;/math&amp;gt;&lt;br /&gt;
# &amp;lt;math&amp;gt;\,\!F_7 = \{ 0, 1,2,3,4,5,6 \}&amp;lt;/math&amp;gt;&lt;br /&gt;
# &amp;lt;math&amp;gt;\,\!F_6 = \{ 0, 1,2,3,4,5 \}&amp;lt;/math&amp;gt; is not a field (counterexample) &lt;br /&gt;
&#039;&#039;&#039;Theorem&#039;&#039;&#039;: &amp;lt;math&amp;gt;\,\!F_P &amp;lt;/math&amp;gt; for &amp;lt;math&amp;gt;p&amp;gt;1&amp;lt;/math&amp;gt; is a field &#039;&#039;&#039;IFF&#039;&#039;&#039; &amp;lt;math&amp;gt;p&amp;lt;/math&amp;gt; is a prime number&lt;br /&gt;
&lt;br /&gt;
== Tedious Theorem ==&lt;br /&gt;
&lt;br /&gt;
...&lt;/div&gt;</summary>
		<author><name>Bofu2007</name></author>
	</entry>
	<entry>
		<id>https://drorbn.net/index.php?title=09-240/Classnotes_for_Tuesday_September_15&amp;diff=7724</id>
		<title>09-240/Classnotes for Tuesday September 15</title>
		<link rel="alternate" type="text/html" href="https://drorbn.net/index.php?title=09-240/Classnotes_for_Tuesday_September_15&amp;diff=7724"/>
		<updated>2009-09-16T01:09:23Z</updated>

		<summary type="html">&lt;p&gt;Bofu2007: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;&amp;lt;math&amp;gt;Insert formula here&amp;lt;/math&amp;gt;&amp;lt;math&amp;gt;Insert formula here&amp;lt;/math&amp;gt;[[Image:Classnotes For Tuesday, September 15.jpg]]&lt;br /&gt;
[[yangjiay:09-240 Classnotes for Tuesday September 15 2009 page 5.jpg]]&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
The real numbers A set &amp;lt;math&amp;gt;\mathbb R&amp;lt;/math&amp;gt; with two binary operators and two special elements &amp;lt;math&amp;gt;0, 1 \in \mathbb R&amp;lt;/math&amp;gt; s.t.&lt;br /&gt;
&lt;br /&gt;
: &amp;lt;math&amp;gt;F1.\quad \forall a, b \in \mathbb R, a + b = b + a \mbox{ and } a \cdot b = b \cdot a&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;F2.\quad \forall a, b, c, (a + b) + c = a + (b + c) \mbox{ and } (a \cdot b) \cdot c = a \cdot (b \cdot c)&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;\mbox{(So for any real numbers } a_1, a_2, ..., a_n, \mbox{ one can sum them in any order and achieve the same result.}&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;F3.\quad \forall a, a + 0 = a \mbox{ and } a \cdot 0 = 0 \mbox{ and } a \cdot 1 = a&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;F4.\quad \forall a, \exists b, a + b = 0 \mbox{ and } \forall a \ne 0, \exists b, a \cdot b = 1&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;\mbox{So } a + (-a) = 0 \mbox{ and } a \cdot a^{-1} = 1&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;\mbox{(So } (a + b) \cdot (a - b) = a^2 - b^2)&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;\forall a, \exists x, x \cdot x = a \mbox{ or } a + x \cdot x = 0&amp;lt;/math&amp;gt;&lt;br /&gt;
: Note: &#039;&#039;&#039;or&#039;&#039;&#039; means &#039;&#039;&#039;inclusive or&#039;&#039;&#039; in math.&lt;br /&gt;
: &amp;lt;math&amp;gt;F5.\quad (a + b) \cdot c = a \cdot c + b \cdot c&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;u&amp;gt;Definition&amp;lt;/u&amp;gt;: A &#039;&#039;&#039;field&#039;&#039;&#039; is a set &#039;&#039;F&#039;&#039; with two binary operators &amp;lt;math&amp;gt;\,\!+&amp;lt;/math&amp;gt;: &#039;&#039;F&#039;&#039;×&#039;&#039;F&#039;&#039; → &#039;&#039;F&#039;&#039;, &amp;lt;math&amp;gt;\times\,\!&amp;lt;/math&amp;gt;: &#039;&#039;F&#039;&#039;×&#039;&#039;F&#039;&#039; → &#039;&#039;F&#039;&#039; and two elements &amp;lt;math&amp;gt;0, 1 \in \mathbb R&amp;lt;/math&amp;gt; s.t.&lt;br /&gt;
: &amp;lt;math&amp;gt;F1\quad \mbox{Commutativity } a + b = b + a \mbox{ and } a \cdot b = b \cdot a \forall a, b \in F&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;F2\quad \mbox{Associativity } (a + b) + c = a + (b + c) \mbox{ and } (a \cdot b) \cdot c = a \cdot (b \cdot c)&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;F3\quad a + 0 = a, a \cdot 1 = a&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;F4\quad \forall a, \exists b, a + b = 0 \mbox{ and } \forall a \ne 0, \exists b, a \cdot b = 1&amp;lt;/math&amp;gt;&lt;br /&gt;
: &amp;lt;math&amp;gt;F5\quad \mbox{Distributivity } (a + b) \cdot c = a \cdot c + b \cdot c&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
== Examples ==&lt;br /&gt;
&lt;br /&gt;
# &amp;lt;math&amp;gt;F = \mathbb R&amp;lt;/math&amp;gt;&lt;br /&gt;
# &amp;lt;math&amp;gt;F = \mathbb Q&amp;lt;/math&amp;gt;&lt;br /&gt;
# &amp;lt;math&amp;gt;\mathbb C = \{ a + bi : a, b \in \mathbb R \}&amp;lt;/math&amp;gt;&lt;br /&gt;
#: &amp;lt;math&amp;gt;i = \sqrt{-1}&amp;lt;/math&amp;gt;&lt;br /&gt;
#: &amp;lt;math&amp;gt;\,\!(a + bi) + (c + di) = (a + c) + (b + d)i&amp;lt;/math&amp;gt;&lt;br /&gt;
#: &amp;lt;math&amp;gt;\,\!0 = 0 + 0i, 1 = 1 + 0i&amp;lt;/math&amp;gt;&lt;br /&gt;
# &amp;lt;math&amp;gt;\,\!F_2 = \{ 0, 1 \}&amp;lt;/math&amp;gt;&lt;br /&gt;
# &amp;lt;math&amp;gt;\,\!F_7 = \{ 0, 1,2,3,4,5,6 \}&amp;lt;/math&amp;gt;&lt;br /&gt;
# &amp;lt;math&amp;gt;\,\!F_6 = \{ 0, 1,2,3,4,5, \}&amp;lt;/math&amp;gt; is not a field (counterexample) &lt;br /&gt;
&#039;&#039;&#039;Theorem&#039;&#039;&#039;: &amp;lt;math&amp;gt;\,\!F_P &amp;lt;/math&amp;gt; for &amp;lt;math&amp;gt;p&amp;gt;1&amp;lt;/math&amp;gt; is a field &#039;&#039;&#039;IFF&#039;&#039;&#039; &amp;lt;math&amp;gt;p&amp;lt;/math&amp;gt; is a prime number&lt;br /&gt;
&lt;br /&gt;
== Tedious Theorem ==&lt;br /&gt;
&lt;br /&gt;
...&lt;/div&gt;</summary>
		<author><name>Bofu2007</name></author>
	</entry>
	<entry>
		<id>https://drorbn.net/index.php?title=09-240/Classnotes_for_Tuesday_September_15&amp;diff=7710</id>
		<title>09-240/Classnotes for Tuesday September 15</title>
		<link rel="alternate" type="text/html" href="https://drorbn.net/index.php?title=09-240/Classnotes_for_Tuesday_September_15&amp;diff=7710"/>
		<updated>2009-09-15T20:50:55Z</updated>

		<summary type="html">&lt;p&gt;Bofu2007: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;[[Image:Classnotes For Tuesday, September 15.jpg]]&lt;/div&gt;</summary>
		<author><name>Bofu2007</name></author>
	</entry>
	<entry>
		<id>https://drorbn.net/index.php?title=Template:09-240/Navigation&amp;diff=7709</id>
		<title>Template:09-240/Navigation</title>
		<link rel="alternate" type="text/html" href="https://drorbn.net/index.php?title=Template:09-240/Navigation&amp;diff=7709"/>
		<updated>2009-09-15T20:40:44Z</updated>

		<summary type="html">&lt;p&gt;Bofu2007: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{| cellpadding=&amp;quot;0&amp;quot; cellspacing=&amp;quot;0&amp;quot; style=&amp;quot;clear: right; float: right&amp;quot;&lt;br /&gt;
|- align=right&lt;br /&gt;
|&amp;lt;div class=&amp;quot;NavFrame&amp;quot;&amp;gt;&amp;lt;div class=&amp;quot;NavHead&amp;quot;&amp;gt;[[09-240]]/[[Template:09-240/Navigation|Navigation Panel]]&amp;amp;nbsp;&amp;amp;nbsp;&amp;lt;/div&amp;gt;&lt;br /&gt;
&amp;lt;div class=&amp;quot;NavContent&amp;quot;&amp;gt;&lt;br /&gt;
{| border=&amp;quot;1px&amp;quot; cellpadding=&amp;quot;1&amp;quot; cellspacing=&amp;quot;0&amp;quot; width=&amp;quot;220&amp;quot; style=&amp;quot;margin: 0 0 1em 0.5em; font-size: small&amp;quot;&lt;br /&gt;
|-&lt;br /&gt;
!#&lt;br /&gt;
!Week of...&lt;br /&gt;
!Notes and Links&lt;br /&gt;
|-&lt;br /&gt;
|align=center|1&lt;br /&gt;
|Sep 7&lt;br /&gt;
|&amp;lt;s&amp;gt;Tue&amp;lt;/s&amp;gt;, [[09-240/About This Class|About]], [[09-240/Classnotes for Thursday September 10|Thu]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|2&lt;br /&gt;
|Sep 14&lt;br /&gt;
|[[09-240:HW1|HW1]],[[09-240/Classnotes for Tuesday September 15|Tue]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|3&lt;br /&gt;
|Sep 21&lt;br /&gt;
|[[09-240:HW2|HW2]], [[09-240/Class Photo|Photo]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|4&lt;br /&gt;
|Sep 28&lt;br /&gt;
|[[09-240:HW3|HW3]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|5&lt;br /&gt;
|Oct 5&lt;br /&gt;
|[[09-240:HW4|HW4]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|6&lt;br /&gt;
|Oct 12&lt;br /&gt;
|&lt;br /&gt;
|-&lt;br /&gt;
|align=center|7&lt;br /&gt;
|Oct 19&lt;br /&gt;
|[[09-240:HW5|HW5]], [[09-240/Term Test|Term Test on Thu]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|8&lt;br /&gt;
|Oct 26&lt;br /&gt;
|[[09-240:HW6|HW6]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|9&lt;br /&gt;
|Nov 2&lt;br /&gt;
|&lt;br /&gt;
|-&lt;br /&gt;
|align=center|10&lt;br /&gt;
|Nov 9&lt;br /&gt;
|[[09-240:HW7|HW7]], &amp;lt;s&amp;gt;Thu&amp;lt;/s&amp;gt;&lt;br /&gt;
|-&lt;br /&gt;
|align=center|11&lt;br /&gt;
|Nov 16&lt;br /&gt;
|[[09-240:HW8|HW8]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|12&lt;br /&gt;
|Nov 23&lt;br /&gt;
|[[09-240:HW9|HW9]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|13&lt;br /&gt;
|Nov 30&lt;br /&gt;
|[[09-240/On The Final Exam|On the final]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|F&lt;br /&gt;
|&lt;br /&gt;
|[[09-240/The Final Exam|Final]]&lt;br /&gt;
|-&lt;br /&gt;
|colspan=3 align=center|[[09-240/Register of Good Deeds|Register of Good Deeds]]&lt;br /&gt;
|-&lt;br /&gt;
|colspan=3 align=center|[[Image:09-240-ClassPhoto.jpg|180px]]&amp;lt;br&amp;gt;[[09-240/Class Photo|Add your name / see who&#039;s in!]]&lt;br /&gt;
|-&lt;br /&gt;
|colspan=3 align=center|[[09-240/Lecture Notes|Lecture Notes]]&lt;br /&gt;
|}&lt;br /&gt;
&amp;lt;/div&amp;gt;&amp;lt;/div&amp;gt;&lt;br /&gt;
|}&lt;/div&gt;</summary>
		<author><name>Bofu2007</name></author>
	</entry>
	<entry>
		<id>https://drorbn.net/index.php?title=Template:09-240/Navigation&amp;diff=7708</id>
		<title>Template:09-240/Navigation</title>
		<link rel="alternate" type="text/html" href="https://drorbn.net/index.php?title=Template:09-240/Navigation&amp;diff=7708"/>
		<updated>2009-09-15T20:30:43Z</updated>

		<summary type="html">&lt;p&gt;Bofu2007: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{| cellpadding=&amp;quot;0&amp;quot; cellspacing=&amp;quot;0&amp;quot; style=&amp;quot;clear: right; float: right&amp;quot;&lt;br /&gt;
|- align=right&lt;br /&gt;
|&amp;lt;div class=&amp;quot;NavFrame&amp;quot;&amp;gt;&amp;lt;div class=&amp;quot;NavHead&amp;quot;&amp;gt;[[09-240]]/[[Template:09-240/Navigation|Navigation Panel]]&amp;amp;nbsp;&amp;amp;nbsp;&amp;lt;/div&amp;gt;&lt;br /&gt;
&amp;lt;div class=&amp;quot;NavContent&amp;quot;&amp;gt;&lt;br /&gt;
{| border=&amp;quot;1px&amp;quot; cellpadding=&amp;quot;1&amp;quot; cellspacing=&amp;quot;0&amp;quot; width=&amp;quot;220&amp;quot; style=&amp;quot;margin: 0 0 1em 0.5em; font-size: small&amp;quot;&lt;br /&gt;
|-&lt;br /&gt;
!#&lt;br /&gt;
!Week of...&lt;br /&gt;
!Notes and Links&lt;br /&gt;
|-&lt;br /&gt;
|align=center|1&lt;br /&gt;
|Sep 7&lt;br /&gt;
|&amp;lt;s&amp;gt;Tue&amp;lt;/s&amp;gt;, [[09-240/About This Class|About]], [[09-240/Classnotes for Thursday September 10|Thu]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|2&lt;br /&gt;
|Sep 14&lt;br /&gt;
|[[09-240:HW1|HW1]],[[09-240/Classnotes for Tue September 15|Tue]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|3&lt;br /&gt;
|Sep 21&lt;br /&gt;
|[[09-240:HW2|HW2]], [[09-240/Class Photo|Photo]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|4&lt;br /&gt;
|Sep 28&lt;br /&gt;
|[[09-240:HW3|HW3]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|5&lt;br /&gt;
|Oct 5&lt;br /&gt;
|[[09-240:HW4|HW4]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|6&lt;br /&gt;
|Oct 12&lt;br /&gt;
|&lt;br /&gt;
|-&lt;br /&gt;
|align=center|7&lt;br /&gt;
|Oct 19&lt;br /&gt;
|[[09-240:HW5|HW5]], [[09-240/Term Test|Term Test on Thu]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|8&lt;br /&gt;
|Oct 26&lt;br /&gt;
|[[09-240:HW6|HW6]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|9&lt;br /&gt;
|Nov 2&lt;br /&gt;
|&lt;br /&gt;
|-&lt;br /&gt;
|align=center|10&lt;br /&gt;
|Nov 9&lt;br /&gt;
|[[09-240:HW7|HW7]], &amp;lt;s&amp;gt;Thu&amp;lt;/s&amp;gt;&lt;br /&gt;
|-&lt;br /&gt;
|align=center|11&lt;br /&gt;
|Nov 16&lt;br /&gt;
|[[09-240:HW8|HW8]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|12&lt;br /&gt;
|Nov 23&lt;br /&gt;
|[[09-240:HW9|HW9]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|13&lt;br /&gt;
|Nov 30&lt;br /&gt;
|[[09-240/On The Final Exam|On the final]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|F&lt;br /&gt;
|&lt;br /&gt;
|[[09-240/The Final Exam|Final]]&lt;br /&gt;
|-&lt;br /&gt;
|colspan=3 align=center|[[09-240/Register of Good Deeds|Register of Good Deeds]]&lt;br /&gt;
|-&lt;br /&gt;
|colspan=3 align=center|[[Image:09-240-ClassPhoto.jpg|180px]]&amp;lt;br&amp;gt;[[09-240/Class Photo|Add your name / see who&#039;s in!]]&lt;br /&gt;
|-&lt;br /&gt;
|colspan=3 align=center|[[09-240/Lecture Notes|Lecture Notes]]&lt;br /&gt;
|}&lt;br /&gt;
&amp;lt;/div&amp;gt;&amp;lt;/div&amp;gt;&lt;br /&gt;
|}&lt;/div&gt;</summary>
		<author><name>Bofu2007</name></author>
	</entry>
	<entry>
		<id>https://drorbn.net/index.php?title=Template:09-240/Navigation&amp;diff=7707</id>
		<title>Template:09-240/Navigation</title>
		<link rel="alternate" type="text/html" href="https://drorbn.net/index.php?title=Template:09-240/Navigation&amp;diff=7707"/>
		<updated>2009-09-15T20:30:10Z</updated>

		<summary type="html">&lt;p&gt;Bofu2007: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{| cellpadding=&amp;quot;0&amp;quot; cellspacing=&amp;quot;0&amp;quot; style=&amp;quot;clear: right; float: right&amp;quot;&lt;br /&gt;
|- align=right&lt;br /&gt;
|&amp;lt;div class=&amp;quot;NavFrame&amp;quot;&amp;gt;&amp;lt;div class=&amp;quot;NavHead&amp;quot;&amp;gt;[[09-240]]/[[Template:09-240/Navigation|Navigation Panel]]&amp;amp;nbsp;&amp;amp;nbsp;&amp;lt;/div&amp;gt;&lt;br /&gt;
&amp;lt;div class=&amp;quot;NavContent&amp;quot;&amp;gt;&lt;br /&gt;
{| border=&amp;quot;1px&amp;quot; cellpadding=&amp;quot;1&amp;quot; cellspacing=&amp;quot;0&amp;quot; width=&amp;quot;220&amp;quot; style=&amp;quot;margin: 0 0 1em 0.5em; font-size: small&amp;quot;&lt;br /&gt;
|-&lt;br /&gt;
!#&lt;br /&gt;
!Week of...&lt;br /&gt;
!Notes and Links&lt;br /&gt;
|-&lt;br /&gt;
|align=center|1&lt;br /&gt;
|Sep 7&lt;br /&gt;
|&amp;lt;s&amp;gt;Tue&amp;lt;/s&amp;gt;, [[09-240/About This Class|About]], [[09-240/Classnotes for Thursday September 10|Thu]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|2&lt;br /&gt;
|Sep 14&lt;br /&gt;
|[[09-240:HW1|HW1]],[[09-240/Classnotes for Thursday September 10|Thu]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|3&lt;br /&gt;
|Sep 21&lt;br /&gt;
|[[09-240:HW2|HW2]], [[09-240/Class Photo|Photo]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|4&lt;br /&gt;
|Sep 28&lt;br /&gt;
|[[09-240:HW3|HW3]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|5&lt;br /&gt;
|Oct 5&lt;br /&gt;
|[[09-240:HW4|HW4]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|6&lt;br /&gt;
|Oct 12&lt;br /&gt;
|&lt;br /&gt;
|-&lt;br /&gt;
|align=center|7&lt;br /&gt;
|Oct 19&lt;br /&gt;
|[[09-240:HW5|HW5]], [[09-240/Term Test|Term Test on Thu]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|8&lt;br /&gt;
|Oct 26&lt;br /&gt;
|[[09-240:HW6|HW6]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|9&lt;br /&gt;
|Nov 2&lt;br /&gt;
|&lt;br /&gt;
|-&lt;br /&gt;
|align=center|10&lt;br /&gt;
|Nov 9&lt;br /&gt;
|[[09-240:HW7|HW7]], &amp;lt;s&amp;gt;Thu&amp;lt;/s&amp;gt;&lt;br /&gt;
|-&lt;br /&gt;
|align=center|11&lt;br /&gt;
|Nov 16&lt;br /&gt;
|[[09-240:HW8|HW8]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|12&lt;br /&gt;
|Nov 23&lt;br /&gt;
|[[09-240:HW9|HW9]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|13&lt;br /&gt;
|Nov 30&lt;br /&gt;
|[[09-240/On The Final Exam|On the final]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|F&lt;br /&gt;
|&lt;br /&gt;
|[[09-240/The Final Exam|Final]]&lt;br /&gt;
|-&lt;br /&gt;
|colspan=3 align=center|[[09-240/Register of Good Deeds|Register of Good Deeds]]&lt;br /&gt;
|-&lt;br /&gt;
|colspan=3 align=center|[[Image:09-240-ClassPhoto.jpg|180px]]&amp;lt;br&amp;gt;[[09-240/Class Photo|Add your name / see who&#039;s in!]]&lt;br /&gt;
|-&lt;br /&gt;
|colspan=3 align=center|[[09-240/Lecture Notes|Lecture Notes]]&lt;br /&gt;
|}&lt;br /&gt;
&amp;lt;/div&amp;gt;&amp;lt;/div&amp;gt;&lt;br /&gt;
|}&lt;/div&gt;</summary>
		<author><name>Bofu2007</name></author>
	</entry>
	<entry>
		<id>https://drorbn.net/index.php?title=Template:09-240/Navigation&amp;diff=7706</id>
		<title>Template:09-240/Navigation</title>
		<link rel="alternate" type="text/html" href="https://drorbn.net/index.php?title=Template:09-240/Navigation&amp;diff=7706"/>
		<updated>2009-09-15T20:29:37Z</updated>

		<summary type="html">&lt;p&gt;Bofu2007: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{| cellpadding=&amp;quot;0&amp;quot; cellspacing=&amp;quot;0&amp;quot; style=&amp;quot;clear: right; float: right&amp;quot;&lt;br /&gt;
|- align=right&lt;br /&gt;
|&amp;lt;div class=&amp;quot;NavFrame&amp;quot;&amp;gt;&amp;lt;div class=&amp;quot;NavHead&amp;quot;&amp;gt;[[09-240]]/[[Template:09-240/Navigation|Navigation Panel]]&amp;amp;nbsp;&amp;amp;nbsp;&amp;lt;/div&amp;gt;&lt;br /&gt;
&amp;lt;div class=&amp;quot;NavContent&amp;quot;&amp;gt;&lt;br /&gt;
{| border=&amp;quot;1px&amp;quot; cellpadding=&amp;quot;1&amp;quot; cellspacing=&amp;quot;0&amp;quot; width=&amp;quot;220&amp;quot; style=&amp;quot;margin: 0 0 1em 0.5em; font-size: small&amp;quot;&lt;br /&gt;
|-&lt;br /&gt;
!#&lt;br /&gt;
!Week of...&lt;br /&gt;
!Notes and Links&lt;br /&gt;
|-&lt;br /&gt;
|align=center|1&lt;br /&gt;
|Sep 7&lt;br /&gt;
|&amp;lt;s&amp;gt;Tue&amp;lt;/s&amp;gt;, [[09-240/About This Class|About]], [[09-240/Classnotes for Thursday September 10|Thu]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|2&lt;br /&gt;
|Sep 14&lt;br /&gt;
|[[09-240:HW1|HW1]][[09-240/Classnotes for Tuesday September 15|Tue]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|3&lt;br /&gt;
|Sep 21&lt;br /&gt;
|[[09-240:HW2|HW2]], [[09-240/Class Photo|Photo]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|4&lt;br /&gt;
|Sep 28&lt;br /&gt;
|[[09-240:HW3|HW3]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|5&lt;br /&gt;
|Oct 5&lt;br /&gt;
|[[09-240:HW4|HW4]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|6&lt;br /&gt;
|Oct 12&lt;br /&gt;
|&lt;br /&gt;
|-&lt;br /&gt;
|align=center|7&lt;br /&gt;
|Oct 19&lt;br /&gt;
|[[09-240:HW5|HW5]], [[09-240/Term Test|Term Test on Thu]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|8&lt;br /&gt;
|Oct 26&lt;br /&gt;
|[[09-240:HW6|HW6]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|9&lt;br /&gt;
|Nov 2&lt;br /&gt;
|&lt;br /&gt;
|-&lt;br /&gt;
|align=center|10&lt;br /&gt;
|Nov 9&lt;br /&gt;
|[[09-240:HW7|HW7]], &amp;lt;s&amp;gt;Thu&amp;lt;/s&amp;gt;&lt;br /&gt;
|-&lt;br /&gt;
|align=center|11&lt;br /&gt;
|Nov 16&lt;br /&gt;
|[[09-240:HW8|HW8]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|12&lt;br /&gt;
|Nov 23&lt;br /&gt;
|[[09-240:HW9|HW9]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|13&lt;br /&gt;
|Nov 30&lt;br /&gt;
|[[09-240/On The Final Exam|On the final]]&lt;br /&gt;
|-&lt;br /&gt;
|align=center|F&lt;br /&gt;
|&lt;br /&gt;
|[[09-240/The Final Exam|Final]]&lt;br /&gt;
|-&lt;br /&gt;
|colspan=3 align=center|[[09-240/Register of Good Deeds|Register of Good Deeds]]&lt;br /&gt;
|-&lt;br /&gt;
|colspan=3 align=center|[[Image:09-240-ClassPhoto.jpg|180px]]&amp;lt;br&amp;gt;[[09-240/Class Photo|Add your name / see who&#039;s in!]]&lt;br /&gt;
|-&lt;br /&gt;
|colspan=3 align=center|[[09-240/Lecture Notes|Lecture Notes]]&lt;br /&gt;
|}&lt;br /&gt;
&amp;lt;/div&amp;gt;&amp;lt;/div&amp;gt;&lt;br /&gt;
|}&lt;/div&gt;</summary>
		<author><name>Bofu2007</name></author>
	</entry>
</feed>