Question Number 76354 by mathmax by abdo last updated on 26/Dec/19
$${calculate}\:\sum_{{n}=\mathrm{1}} ^{\infty} \left(−\mathrm{1}\right)^{{n}} \:{arctan}\left(\frac{\mathrm{1}}{{n}^{\mathrm{2}} \:+{n}}\right) \\ $$
calculate-n-1-1-n-arctan-1-n-2-n-