My professor gave two problems which are,
1) $f(x)=3x$ , $-L<x<L$ And $f(x+2L)=f(x)$
2) $f(x)=3x$ , $0<x<2L$ And $f(x+2L)=f(x)$
And we have to find the Fourier series of each function. We gotta find $a0$ , $an$ and $bn$ coefficients separately and combine those to get the series.
I'm quite confused because these two questions are same to me. I have poor knowledge of fourier series. So can someone explain are both give same answer or different answers.