The principal value of $\sin ^{-1}\left(\sin \frac{3 \pi}{4}\right)$ is

The principal value of $\sin ^{-1}\left(\sin \frac{3 \pi}{4}\right)$ is
  1. $\frac{\pi}{4}$
  2. $\frac{3 \pi}{4}$
  3. $\frac{-\pi}{4}$
  4. $\frac{5 \pi}{4}$

Solution

$\begin{aligned} \sin ^{-1}\left(\sin \frac{3 \pi}{4}\right) & =\sin ^{-1}\left[\sin \left(\pi-\frac{\pi}{4}\right)\right] \\ & =\sin ^{-1}\left(\sin \frac{\pi}{4}\right) \\ & =\frac{\pi}{4}\end{aligned}$

Asked in: MHT CET 2023 (13 May Shift 2)

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