PHP Manual
Math Functions
Inverse hyperbolic tangent

atanh

(PHP 4 >= 4.1.0, PHP 5)

atanh — Inverse hyperbolic tangent

Description

float atanh ( float $arg )

Returns the inverse hyperbolic tangent of arg, i.e. the value whose hyperbolic tangent is arg.

Parameters

arg: The argument to process

Return Values

Inverse hyperbolic tangent of arg

Changelog

Version	Description
5.3.0	This function is now available on all platforms

See Also

tanh() - Hyperbolic tangent
atan() - Arc tangent
asinh() - Inverse hyperbolic sine
acosh() - Inverse hyperbolic cosine