Table of Contents

Syntax

float acos(float $val)

(PHP 4 >= 4.07, PHP 5)

$val Value to compute the arc cosine for.
RETURNS Computes the trigonometry function inverse hyperbolic cosine for the degree in radians ($val).

What it Does

This function computes the inverse hyperbolic cosine for the argument $val which is the degree in radians.

Note: This function is not currently available for PHP on Windows.

Example

// compute the inverse hyperbolic cosine for 1.4 radians
echo 'acosh(1.4) = ' . acos(1.4);