# Simple question about fourier series

1. Oct 31, 2013

### Dassinia

Hello,
Find the Fourier serie of f(x)=|sin(x)| on the interval (-1,1)

I'm just a little confused, does that mean that I have to integrate from -1 to 1 to find the coefficients ? Because the formula of the coefficients is in terms of the period T, for this function the period is pi. Or do I have to consider it only in -1,1 and take the period T=2 ?

Thanks

Last edited: Oct 31, 2013
2. Oct 31, 2013

### vela

Staff Emeritus
For a homework problem, it seems like the given interval might be a typo or the function was supposed to be $\lvert \sin \pi x \rvert$; however, there's no real reason the interval couldn't be (-1, 1) for the given function. I'd check with your instructor if I were you.

3. Oct 31, 2013

### Dassinia

It's not a homework, it's an exercise in a previous exam..
the exam is tomorrow and I just saw this exercise..

EDIT: I sent an email to an instructor, and I had my answer !

Last edited: Oct 31, 2013