atan()

atan - Arc tangent

Syntax

float atan (float $arg)

Arguments

• arg - The argument to process

Description

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.

Version

PHP 4, 5

Return value

The arc tangent of arg in radians.