Answer
$\theta=\dfrac{\pi}{2}$
Work Step by Step
We know that the trigonometric function $\sin^{-1} (1)$ has domain $[-1,1]$ and the range is: $[-\dfrac{\pi}{2}, \dfrac{\pi}{2}]$.
So, $\theta = \sin^{-1} (1) $
This implies that: $\theta=\dfrac{\pi}{2}$
