 Ask Remember Me? cheychey87 Posts: 1, Reputation: 1 New Member #1 Mar 24, 2011, 10:18 PM
prove that cos((pi/2-x)-y)=sin(x y)?
Help help trig trig help ebaines Posts: 12,132, Reputation: 1307 Expert #2 Mar 25, 2011, 07:37 AM

Please note that for some reason this site loses any "+" signs that you put in the subject header for your question. I assume what you mean is this:

This is a siimple use of the identities for and , and also use of and .

Alternatively if you recognize that and apply the identity for then it comes right out.

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