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trigonometry - Is $\sin^3 x=\frac{3}{4}\sin x - \frac{1}{4}\sin 3x$? - Mathemati

Continuing from my comment to bgins's answer, one can start from the (defining) Chebyshev polynomial identity $$T_{2n-1}(\cos\,x)=\cos((2n-1)x)$$ and make the substitution $x=\frac{\pi}{2}-z$ to yield the identity $$T_{2n-1}(\sin&#...

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