SOLUTION: Prove that each is an identity sin 3 x = 3 sin x - 4 sin^3 x

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Question 443331: Prove that each is an identity
sin 3 x = 3 sin x - 4 sin^3 x
Answer by richard1234(7193) About Me  (Show Source):
You can put this solution on YOUR website!
Use the sum formula for sine:









Replace cos^2(x) with 1 - sin^2(x):







Hence, the statement is an identity.