- #1
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Homework Statement
how to expand f(x)=x^2, -pi<x<pi as Fourier series
answer at back of the book says:
f(x)=((pi^2)/3)+4sigma(from 1 to infinity) [((-1)^n)/(n^2)]cos nx
i tried the a(n) b(n) stuff but i don't see where they get the n^2 in the denominator from
when i integrated to try to find a(n) i get n on the denominator