Find the Fourier Series of $f(x)=\begin{cases} -3 & x \in(-5,0) \\ 3 & x \in(0, 5) \end{cases}$
I know that: $$a_0=0$$$$a_n=0$$but when I try to $b_n$ I have
$$b_n=\frac{-6\cos \left(5n\right)+6}{n}$$
How can I interpret my Fourier series?
Can u Help me? :c