Hello,

I am having trouble simplifying this identity [cos4x= 2cos^2 2x-1]. I thought I could solve it with the double angle identity, but the 2x seems to be getting in the way. Can I remove the 2x and multiply it by the identity cos2x?

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- May 18th 2010, 02:03 PMSedgewick19Identity proof
Hello,

I am having trouble simplifying this identity [cos4x= 2cos^2 2x-1]. I thought I could solve it with the double angle identity, but the 2x seems to be getting in the way. Can I remove the 2x and multiply it by the identity cos2x? - May 18th 2010, 02:08 PMDeadstar
- May 19th 2010, 06:31 AMSedgewick19
Thanks, I thought that may have been the way the solve the problem, but I was afraid that it was too easy.