The value of $sin^{-1} (sin 10)$, is |
$3\pi - 10$ $10- 3\pi $ $3\pi + 10$ $4\pi - 10$ |
$3\pi - 10$ |
We know that $ sin^{-1}(sin \theta) = \theta , $ if $-\frac{\pi}{2} ≤ θ ≤ \frac{\pi}{2}$. Here, θ = 10 radians which does not lie between $-\frac{\pi}{2}$ and $\frac{\pi}{2}$. But, $ 3\pi - \theta $ i.e $3\pi - 10$ lies, netween $-\frac{\pi}{2}$ and $\frac{\pi}{2}$. Also, $sin(3\pi - 10) = sin 10.$ ∴ $ sin^{-1}(sin 10)=sin^{-1}(sin (3\pi - 10))= 3\pi - 10 $ |