Fourier series odd and even functions

[robertjford80]

Homework Statement

The Attempt at a Solution

I don't understand the step above. It has something to do with this equation

I think. I'm supposed to expand it into an appropriate Fourier series.

 

[LCKurtz]

You haven't given us enough information. What is f(x)? You were probably given a function and asked to expand it in a sine series.

 

[HallsofIvy]

The "step above" is just applying the definition of the Fourier series:
Are you saying you do not know what that is?

 

[robertjford80]

here is some more info

I don't understand why they're adding the sin on to that last step.

 

[micromass]

I don't understand why they're adding the sin on to that last step.

What is the definition of a Fourier series?