# Fourier series

Discussion in 'Homework Help' started by ericyeoh, Oct 9, 2011.

1. ### ericyeoh Thread Starter Active Member

Aug 2, 2009
58
0
Guys,

Need guidance from u guys, if question given determine all then non-zero fourier coefficient in a periodic function f(t) = 5 +cos^2 (t) V.

Should i start to integrate the function from -infinity to infinity?

F(t) = A0/2 + Intergrate ( an cos wt + bn sin wt) ?

2. ### t_n_k AAC Fanatic!

Mar 6, 2009
5,448
784
Keep in mind that one may re-write

$cos^2t=\frac{1+cos2t}{2}$

using the known trig identities.

Make the substitution for the cos^2t term into the given f(t).

Henceforth your problem in finding the non-zero Fourier series coefficients reduces almost to a solution by inspection.