let f:[1/2,1]→[-1,1] is given by f(x)=4x3-3x then f-1(x) is given by
1. cos (1/3 cos-1x)
2. 3cos(cos-1x)
3. 3sin(sin-1x)
4. 3sin-1(sinx)
5. sin(1/3 sin-1x)
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3 Answers
1sir,i have already tried it x=cosA then 1/2 ≤ cosA ≤1 f(cosA)=cos3A so f-1(cos3A)=cosA we need to find out f-1(x) .. so x=cos3A
cos-1x=3A
So A=1/3 (cos-1(x))
so cos A =cos (1/3(cos-1(x))
so f-1(x)=cos (1/3(cos-1(x))
well the answer matches but is the solution correct?!?!?!