$$\sum_{1} ^{\infty}\frac{\sin^{n} x +2}{x^{2n}+1}$$
I have no idea how to find the convergence interval.
$$ \begin{split} |\sin^n x| &\le 1\\ \frac {\sin^n x + 2}{x^{2n} + 1} &< \frac {3}{x^{2n}} \end{split} $$
And by the comparison test the integral converges whenever $|x| > 1$
Copyright © 2021 JogjaFile Inc.
$$ \begin{split} |\sin^n x| &\le 1\\ \frac {\sin^n x + 2}{x^{2n} + 1} &< \frac {3}{x^{2n}} \end{split} $$
And by the comparison test the integral converges whenever $|x| > 1$