Hi
Did you see the rough box?
We use the formula
cos 2x = 2cos2 x - 1
Putting x = 2x
cos 2(2x) = 2 cos2 (2x) - 1
cos 4x = 2 cos2 2x - 1
Written on July 5, 2017, 10:03 a.m.
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Answer of this question
y u put 2(cos2x)^2?
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