Math Functions
PHP Manual

acos

(PHP 4, PHP 5)

acosArc cosine

Description

float acos ( float $arg )

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.

Parameters

arg

The argument to process

Return Values

The arc cosine of arg in radians.

See Also


Math Functions
PHP Manual