Modern 2:Exam 1 Overview

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Revision as of 16:46, 6 March 2006

I will drop your lowest exam grade. Second hourly exam is next Monday. Recall, the hourlies make up 40% of the grade. Course requirements

concerned $1.9 = 3$ and $π = 3$ so $1.9π = 6$

lots of people messed up exponents when doing division. $109 / 10 - 9 = 10 18$
break up complicated numerical factors involving multiplications and divisions into small pieces. First do the numerator, then do the denominator and then get your final estimate.
lots of people messed up: $| e I k x | 2$ . This is 1!
some people used $|e^{I k_0 x}|^2$ and some used $|e^{-Ik_0 x}|^2$ .

I didn't take off for this. But it does change the sign of the momentum.

of the distribution is $x 0$ . You can show this by integration, but it should be sufficiently well known that you merely state it as a fact.

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 * break up complicated numerical factors involving multiplications and divisions into small pieces.  First do the numerator, then do the denominator and then get your final estimate.
 * lots of people messed up: <math> |e^{I k x}|^2 </math>.  This is 1!
-* some people used <math> |e^{I k_0 x}|^2 </math> and some used <math> |e^{I -k_0 x}|^2 </math>.
+* some people used <math> |e^{I k_0 x}|^2 </math> and some used <math> |e^{-Ik_0 x}|^2 </math>.
 I didn't take off for this.  But it does change the sign of the momentum.
 * A Gaussian <math>e^{(x-x_0)^2/2\sigma^2}</math> is centered at <math>x_0</math>.  I.e., the mean