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authorOpheliar99 <>2010-07-04 02:09:23 +0000
committerbnewbold <bnewbold@adelie.robocracy.org>2010-07-04 02:09:23 +0000
commit0f404e5abfa71351a28ced3dda6e737edceb6e28 (patch)
tree896adc15a49e8f94ce46b68a9bbe8d0c226f028d /Problem Set 2.page
parent4b5a01be19b578fb1e51860aabd18edd4848bdde (diff)
downloadafterklein-wiki-0f404e5abfa71351a28ced3dda6e737edceb6e28.tar.gz
afterklein-wiki-0f404e5abfa71351a28ced3dda6e737edceb6e28.zip
posted solutions of 2 and 3 in pset2
Diffstat (limited to 'Problem Set 2.page')
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diff --git a/Problem Set 2.page b/Problem Set 2.page
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@@ -44,13 +44,18 @@ $\int_0^{2\pi} \sin^4(x) dx = \frac{{e^{ix}-e^{-ix}}^4}{16}$
$ = \frac{e^{i4x}+e^{-4ix}-4 e^{i2x} -4 e^{-i2x}+6}{16}$
If we express any periodic function $f(x)$ as
+
$f(x) = \sum a_n f_n(x)$, where $f_n(x) = \frac{e^{inx}}{\sqrt{2\pi}}$, $f_0(x) = \frac{1}{\sqrt{2\pi}}$,
The Fourier coefficients for the above functions are:
+
$a_{-4} = a_{4} = \sqrt{2\pi} \times 1/16$, $a_{-2} = a_{2} = - \sqrt{2\pi} \times 4/16$, $a_0 = \sqrt{2\pi} \times 6/16$
Since $a_m = < f_m, f >$,
-$\int_0^{2\pi} \sin^4(x) dx = <1, f> = \sqrt{2\pi} \times <f_0, f> = \frac{3 \pi}{4}$
+
+$\int_0^{2\pi} \sin^4(x) dx = <1, f> = \sqrt{2\pi} \times $<f_0, f>$
+
+= \sqrt{2\pi} \times a_0 = \frac{3 \pi}{4}$
## Cardinality