Determine if the series is convergent $$\sum_{n=0}^\infty \frac {\ln n} { \sinh (in)}$$
I am stuck here guys, any hint? :/ I have tried abel test, but it didn't help. Edit: Jose reminded me to check the main part's limit, which isn't zero.
Determine if the series is convergent $$\sum_{n=0}^\infty \frac {\ln n} { \sinh (in)}$$
I am stuck here guys, any hint? :/ I have tried abel test, but it didn't help. Edit: Jose reminded me to check the main part's limit, which isn't zero.
Copyright © 2021 JogjaFile Inc.
It diverges, since you don't have $\displaystyle\lim_{n\to\infty}\frac{\ln n}{\sinh(in)}=0$. In fact$$\left|\frac{\ln n}{\sinh(in)}\right|=\left|\frac{\ln n}{i\sin n}\right|=\left|\frac{\ln n}{\sin n}\right|\geqslant\ln n.$$