Convergence interval of series

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$$\sum_{1} ^{\infty}\frac{\sin^{n} x +2}{x^{2n}+1}$$

I have no idea how to find the convergence interval.

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$$ \begin{split} |\sin^n x| &\le 1\\ \frac {\sin^n x + 2}{x^{2n} + 1} &< \frac {3}{x^{2n}} \end{split} $$

And by the comparison test the integral converges whenever $|x| > 1$