COS }^{-1}}
X
=2{{\sin }^{-1}}x\] \[\Rightarrow \
FRAC
{\pi }{2}-{{\sin }^{-1}}x=2{{\sin }^{-1}}x\] \[\Rightarrow \frac{\pi }{2}=3{{\sin }^{-1}}x\Rightarrow {{\sin }^{-1}}x=\frac{\pi }{
6
}\] So, \[x=\sin \frac{\pi }{6}=\frac{1}{2}\]