acos()

acos - Arc cosine

Syntax

float acos (float $arg)

Arguments

• arg - The argument to process

Description

Returns the arc cosine of arg in radians. acos() is the complementary function of cos(), which means that a==cos(acos(a))for every value of a that is within acos() ' range.

Version

PHP 4, 5

Return value

The arc cosine of arg in radians.