$y=\tan ^{-1}(1)+\cos ^{-1}\left(-\frac{1}{2}\right)+\sin ^{-1}\left(-\frac{1}{2}\right)$ Now put the value of principal :$ \begin{aligned} \tan ^{-1}(1) & =\frac{\pi}{4}, \cos ^{-1}\left(-\frac{1}{2}\right)=\pi-\cos ^{-1}\left(\frac{1}{2}\right) \\ & =\pi-\frac{\pi}{3}=\frac{2 \pi}{3} \\ \sin ^{-1}\left(-\frac{1}{2}\right) & =-\sin ^{-}\left(\frac{1}{2}\right)=-\frac{\pi}{6} \end{aligned} $ Put these values in the equation (i) : $\begin{aligned} y & =\frac{\pi}{4}+\frac{2 \pi}{3}-\frac{\pi}{6}=\frac{3 \pi+8 \pi-2 \pi}{12} \\ & =\frac{9 \pi}{12}=\frac{3 \pi}{4} \text {}\end{aligned}$
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.