• Answer of this question

    y u put 2(cos2x)^2?
    Davneet Singh's image
    Davneet Singh

    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.