Mathematics - Inverse Trigonometric Function Question with Solution | TestHub

$y={\cos }^{-1}\left(\frac{7}{2}(1+\cos 2x)+\sqrt{\left({\sin }^{2}x-48{\cos }^{2}x\right)}\sin x\right)$ $={\cos }^{-1}\left((7\cos x)(\cos x)+\sqrt{1-49{\cos }^{2}x}\sqrt{1-{\cos }^{2}x}\right)$ $={\cos }^{-1}(\cos x)-{\cos }^{-1}(7\cos x)[\because \cos x<7\cos x]$ $=x-{\cos }^{-1}(7\cos x)$