Hi, im trying to prove that $\sum_{k=1}^\infty\text{cosech}(kx)$ u.c. for $|x|\geq\delta>0$.
2. Sorry, already solved: $|\text{cosech}(nx)|\leq|\text{cosech}(n\delta)|\le q \frac{12}{n^3\delta^3}=M_n$ (Taylor for $e^{n\delta}$)