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Prove that cos3x/cosx-cos6x/cos2x=2(cos2x-cos4x)
9 years ago

Answers

Steve
cos3x = cosx(2cos2x - 1)
similarly,
cos6x = cos2x(2cos4x - 1)

I think you can see where this is going, right?
9 years ago
Melchert
Yes
4 years ago

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