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MathNet 2009-part-02 — 175 problems (EN–VI) Question 13

Math Olympiad Vault · MathNet 2009-part-02 — 175 problems (EN–VI)

Question 13

Let $\theta_1, \theta_2, \dots, \theta_{2008}$ be real numbers. Find the maximum value of
$$ \sin \theta_1 \cos \theta_2 + \sin \theta_2 \cos \theta_3 + \dots + \sin \theta_{2007} \cos \theta_{2008} + \sin \theta_{2008} \cos \theta_1. $$