Find the Fourier Series of the function periodic extension of the function
f(t) = t^2, -1 <= t <= 1.
Is the function f(x) equal to the Fourier series for all x in R?
Using this expansion, find
a. sum_{n=1}^{infinity} (-1)^n / n^2 (Hint: Plug in t = 0 in the Fourier series and simplify).
b. sum_{n=1}^{infinity} 1 / n^2