Definition:Inverse Hyperbolic Secant/Complex/Definition 1

Definition
The inverse hyperbolic secant is a multifunction defined as:


 * $\forall z \in \C_{\ne 0}: \map {\sech^{-1} } z := \set {w \in \C: z = \map \sech w}$

where $\map \sech w$ is the hyperbolic secant function.

Also see

 * Equivalence of Definitions of Complex Inverse Hyperbolic Secant