ChallengeMediumTelescoping & Recursion ShareTelescoping & Recursion · Medium problemEvaluate ∑n=1∞arctan (1n2+n+1)\displaystyle\sum_{n=1}^{\infty}\arctan\!\left(\dfrac{1}{n^{2}+n+1}\right)n=1∑∞arctan(n2+n+11).Check Show answer Walk through it step by step Practice more like this Review this concept