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2013 preRMO p2, S_n=\sum_{k=0}^{n}\frac{1}{\sqrt{k+1}+\sqrt{k}}

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August 8, 2019
Sumalgebra

Problem Statement

Let Sn=k=0n1k+1+kS_n=\sum_{k=0}^{n}\frac{1}{\sqrt{k+1}+\sqrt{k}}. What is the value of n=1991Sn+Sn1\sum_{n=1}^{99}\frac{1}{S_n+S_{n-1}} ?