Q41 / 160 · AP EAMCET 2003 · Mathematics
$\sin \mathrm{h}^{-1}\left(2^{3 / 2}\right)$ is equal to :
- Correct answerA$\log (3+\sqrt{8})$
- B$\log (3-\sqrt{8})$
- C$\log (2+\sqrt{18})$
- D$\log (\sqrt{8}+\sqrt{27})$
Solution
We have
$\sin h^{-1} x=\log \left\{x+\sqrt{x^2+1}\right\}$
$\sin h^{-1}(2)^{3 / 2}=\log \left\{2^{3 / 2}+\sqrt{\left(2^{3 / 2}\right)^2+1}\right\}$
$=\log \{\sqrt{8}+\sqrt{8+1}\}=\log \{3+\sqrt{8}\}$
Hence, the correct answer is option: 'A'.