SOLUTION: simplify: sinx . cosx . cos 2x Thank you

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Question 707070: simplify:
sinx . cosx . cos 2x
Thank you
Answer by mouk(232) About Me  (Show Source):
You can put this solution on YOUR website!
Use the identity:
+sin%28A%2BB%29=sinAcosB%2BcosAsinB+
giving +sin2A=2sinAcosA+, or, +sinxcosx+=%281%2F2%29sin2x

So then:
+%28sinx%29%28cosx%29%28cos+2x%29+=%281%2F2%29sin2xcos2x=%281%2F4%29sin4x+