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Arccotangent Sum

Geometry Level 4

Evaluate \[\cot{(\cot^{-1}{(7)}+\cot^{-1}{(13)}+\cot^{-1}{(21)}+\cot^{-1}{(31)})}\]

Excel in math and science

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It's hard to learn from lectures and videos

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including olympiad champions, researchers, and professionals.

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by Ikkyu San

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