Practice problem
Let S=∑n=0∞cot−1(n2+n+1)S = \sum_{n=0}^{\infty} \cot^{-1}(n^2+n+1)S=∑n=0∞cot−1(n2+n+1). Find π/S\pi/Sπ/S.
Source: HMMT February 2001
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Type a concept, like “slope” or “photosynthesis”.
