Q64 / 180 · KCET 2016 · Mathematics
The value of \( \sin ^{-1}\left(\cos \frac{53 \Pi}{5}\right) \) is
- A\( 3 \frac{\Pi}{5} \)
- B\(-3 \frac{\Pi}{5} \)
- C\( \frac{\Pi}{10} \)
- Correct answerD\( -\frac{\Pi}{10} \)
Solution
Given that, \( \sin ^{-1}\left(\cos \frac{53 \pi}{5}\right) \)
\( =\sin ^{-1}\left\{\cos \left(10 \Pi+\frac{3 \pi}{5}\right)\right\} \)
\( =\sin ^{-1}\left(\cos \frac{3 \pi}{5}\right) \)
\( =\sin ^{-1}\left(\cos \left(\frac{\Pi}{2}+\frac{\Pi}{10}\right)\right) \)
\( =\sin ^{-1}\left(-\sin \left(\frac{\Pi}{10}\right)\right) \)
\( =\sin ^{-1}\left(\sin \left(-\frac{\Pi}{10}\right)\right)=\frac{-\Pi}{10} \)
Hence, the correct answer is option: 'D'.