Question

Find the value of ${\sin }^{-1}1$.

Answer 1

Let $y={\sin }^{-1}1={\sin }^{-1}\left(\sin \pi /2\right)=\pi /2$
$[\because \sin \pi /2=1$ and ${\sin }^{-1}\left(\sin \theta \right)=\theta$ for $-\pi /2\le \theta \le \pi /2]$.