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 Question from James, a student: I need to prove trig identities, and I can't figure this one out 1 + sinx - cosx        1 - cosx -------------------- = ------------- 1 + sinx + cosx          sinx

James,

Try cross-multiplying -- that is, multiply both sides of the identity by (sin x)(1 + sin x + cos x). If the modified identity holds for all x (except where multiplying by 0), then so does the original.

Chris

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