If sin x + sin2x + sin3x= 1, then cos6x-4cos4x+8cos2x =

If sin x + sin2x + sin3x= 1, then cos6x-4cos4x+8cos2x =


1 Answers

879 Points
12 years ago

Dear student,

It's probably not in the spirit of the question but you can just solve that cubic numerically and get sin(x) = 0.5437. Then using cos^2(x) = 1- sin^2(x) you can easily evaluate it.

The answer will be 4.

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All the best.

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Sagar Singh

B.Tech, IIT Delhi

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