Definition:Inverse Sine/Real

Definition
Let $x \in \R$ be a real number such that $-1 \le x \le 1$.

The inverse sine of $x$ is the multifunction defined as:
 * $\map {\sin^{-1} } x := \set {y \in \R: \map \sin y = x}$

where $\map \sin y$ is the sine of $y$.