Math Functions
PHP Manual

atan

(PHP 4, PHP 5)

atanArc tangent

Description

float atan ( float $arg )

Returns the arc tangent of arg in radians. atan() is the complementary function of tan(), which means that a==tan(atan(a)) for every value of a that is within atan()'s range.

Parameters

arg

The argument to process

Return Values

The arc tangent of arg in radians.

See Also


Math Functions
PHP Manual