- #1
ramdayal9
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Homework Statement
Let [itex]f(x)=x[/itex] on [itex] [-\pi,\pi) [/itex] and peridically extended. Compute the Fourier series and hence show:
[itex] \sum_{n \geq 1,nodd} \frac{1}{n^2} = \frac{\pi^2}{8} [/itex] and [itex] \sum_{n \geq 1} \frac{1}{n^2} = \frac{\pi^2}{6} [/itex]
Homework Equations
Parseval's equality
The Attempt at a Solution
I computed the Fourier series to be [itex] -\sum_{n=1,nodd} \frac{4}{n^2 \pi} e^{inx}+\frac{\pi}{2} [/itex] (even terms [itex]\hat{f}(n)=0 [/itex]) and proved the first sum (letting x=0).
How would I compute the second part? how do i get the whole sum from this? I tried to slipt the sum into even and odd parts, but i don't know how to compute the even sum when I don't have any terms for the even sum! thanks