We have calculated exact, rational values for sin r when r = 0, 1, 1 2 . Surprisingly
Chapter 9, Problem 9.2.20(choose chapter or problem)
We have calculated exact, rational values for sin r when r = 0, 1, 1 2 . Surprisingly, these are the only rational values of sin r when r is rational. Prove the following identity, which is used to obtain the result:2 2 cos((n+1)) = (2 cos )(2 cos(n))2 cos((n1)).
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