PHP Manual
Math Functions
Inverse hyperbolic cosine

acosh

(PHP 4 >= 4.1.0, PHP 5)

acosh — Inverse hyperbolic cosine

Description

float acosh ( float $arg )

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

Parameters

arg: The value to process

Return Values

The inverse hyperbolic cosine of arg

Changelog

Version	Description
5.3.0	This function is now available on all platforms

See Also

cosh() - Hyperbolic cosine
acos() - Arc cosine
asinh() - Inverse hyperbolic sine
atanh() - Inverse hyperbolic tangent