Verify cosxcosy = 1/2 [cos(x+y) + cos(x-y)] I think the inner part is goofing me up. I never get far . Please help.
Last edited by dazedandmathfused; October 12th 2011 at 09:01 PM.
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Originally Posted by dazedandmathfused Verify cosxcosy = 1/2 [cos(x+y) + cos(x-y)] I think the inner part is goofing me up. I never get far . Please help.
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