flightwingsd2

2022-06-27

Proving whether the series $\frac{\mathrm{cos}\left(n\right)}{n}$ is absolutely convergent

Expert

Hint:
$\frac{|\mathrm{cos}n|}{n}\ge \frac{{\mathrm{cos}}^{2}n}{n}=\frac{1-\mathrm{cos}2n}{2n}.$

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