asinh() [6/8]

var stan::math::asinh ( const var &  x )

inline

The inverse hyperbolic sine function for variables (C99).

The derivative is defined by

\(\frac{d}{dx} \mbox{asinh}(x) = \frac{x}{x^2 + 1}\).

\[ \mbox{asinh}(x) = \begin{cases} \sinh^{-1}(x) & \mbox{if } -\infty\leq x \leq \infty \\[6pt] \textrm{NaN} & \mbox{if } x = \textrm{NaN} \end{cases} \]

\[ \frac{\partial\, \mbox{asinh}(x)}{\partial x} = \begin{cases} \frac{\partial\, \sinh^{-1}(x)}{\partial x} & \mbox{if } -\infty\leq x\leq \infty \\[6pt] \textrm{NaN} & \mbox{if } x = \textrm{NaN} \end{cases} \]

\[ \sinh^{-1}(x)=\ln\left(x+\sqrt{x^2+1}\right) \]

\[ \frac{\partial \, \sinh^{-1}(x)}{\partial x} = \frac{1}{\sqrt{x^2+1}} \]

Parameters

x	The variable.

Returns

Inverse hyperbolic sine of the variable.

Definition at line 59 of file asinh.hpp.