SOLUTION: prove that sin(B+2C)+sin(C+2A)+sin(A+2B)=4sin(B-C/2)+sin(C-A/2)+cos(A-B/2).

SOLUTION: prove that sin(B+2C)+sin(C+2A)+sin(A+2B)=4sin(B-C/2)+sin(C-A/2)+cos(A-B/2).

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Question 327934: prove that sin(B+2C)+sin(C+2A)+sin(A+2B)=4sin(B-C/2)+sin(C-A/2)+cos(A-B/2).
Answer by Fombitz(32388) (Show Source): You can put this solution on YOUR website!
Here are the identities you need,

I'll start you out with the first term.

Continue in this fashion and then work backwards to get the right hand side.
Watch the signs and the A,B, and C's.
Good luck.
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