The fourier coefficients of ${f} \in C_{PW}^0$ are given by $\widehat f(n)=(-i)^n(\frac{3i}{4n}+\frac{1}{2\pi n^2}) $ for $n \ne 0$.
Find where $f$ is discontinuous and what is its jump there?
it's enough to find estimates to the exact answer.
Honestly i don't know how to even start.