# Trigonometry! #36

Geometry Level 4

Suppose $sin^{3} x \sin 3x = \displaystyle \sum_{m=0}^{n} c_{m} \cos mx$ is an identity in $$x$$ where $$c_{0} , c_{1} , ... , c_{n}$$ are constants, and $$c_{n}≠0$$. Then find the value of n.

This problem is part of the set Trigonometry.

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