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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- Oct 12th 2011, 06:27 PMdazedandmathfusedokay the last verify problem i have problems with
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. - Oct 12th 2011, 08:34 PMProve ItRe: okay the last verify problem i have problems with