# Math Help - Fourier's Serier

1. ## Fourier's Serier

f(x)= x^2 , 0 <= x <= 1

x , -1 <= x <= 0

I found a[o] put having trouble finding a[n].

2. Where are you stuck finding $a_n$? I think you need to integrate by parts twice for the first and one time for the second.