Prove that `cos(2pi)/(15)cos(4pi)/(15)cos(8pi)/(15)cos(14pi)/(15)=1/(16)`

Explanation

To prove that

\[ \cos\left(\frac{2\pi}{15}\right) \cos\left(\frac{4\pi}{15}\right) \cos\left(\frac{8\pi}{15}\right) \cos\left(\frac{14\pi}{15}\right) = \frac{1}{16}, \]

we will start with the left-hand side and manipulate it step by step.

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