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Prove the identity on sines

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September 22, 2010
trigonometryalgebrapolynomialTrigonometric IdentitiesIMO Shortlist

Problem Statement

Prove that for all nNn \in \mathbb N the following is true: 2nk=1nsinkπ2n+1=2n+12^n \prod_{k=1}^n \sin \frac{k \pi}{2n+1} = \sqrt{2n+1}