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| Math Central | Quandaries & Queries |
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Question from Jeff, a student: i cannot prove this trigonometric identity. please help! (cos x)^3 – (sin x)^3 = (cos x –sin x) (1+cosxsinx) |
Jeff,
Use of the fact that u3 - v3 = (u-v)(u2 + uv + v2). (Just let u = cos x and v = sin x. It will come down to a familiar identity.)
Chris
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