Answer
There is no angle $\theta$ such that $sin~\theta = 3$
Therefore, $sin^{-1}~3$ is not defined
Work Step by Step
Let $\theta = sin^{-1}~3$
Then: $sin~\theta = 3$
However: $-1 \leq sin~\theta \leq~1$, for all angles $\theta$
There is no angle $\theta$ such that $sin~\theta = 3$
Therefore, $sin^{-1}~3$ is not defined