Hi. Well, I have to demonstrate that
Using a previous result of a Fourier series for f(t)=1 if 0<t<1, f(t)=0 if -1<t<0.
I've found that:
I think this result, the series expansion for the function is right. But when I've tried to demonstrate what the problem asks me I get to an absurd, so I'm not sure where the error is.
This is what I did:
Working from here:
So, I'm doing something wrong. Perhaps you can see more clearly where am I committing the mistake.