how would you verify (cosx-cosy)/(sinx+siny) + (sinx-siny)/(cosx+cosy) =0

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- May 3rd 2009, 12:05 PMwolfxpaxverifying a trigonometric identity
how would you verify (cosx-cosy)/(sinx+siny) + (sinx-siny)/(cosx+cosy) =0

- May 3rd 2009, 12:56 PMOpalg
Don't forget to use parentheses (as in red above) to make the meaning unambiguous. Also, it looks to me as though one of those – signs should be a +.

Anyway, to prove the identity, put the left side over a common denominator, and see what happens to the numerator.