If `y=cos^(-1)(2x)+2cos^(-1)sqrt(1-4x^2),\ \ 0

Explanation

Given `y=\cos ^{-1}(2 x)+2 \cos ^{-1} \sqrt{1-4 x^{2}}`



Put `2 x=\sin \theta`



Thus, `y=\cos ^{-1}(\sin \theta)+2 \cos ^{-1} \sqrt{(1-\sin 2 \theta)}`
$$
\begin{aligned}
&y=\cos ^{-1}(\sin \theta)+2 \cos ^{-1}(\cos \theta) \\
...