atan
(PHP 4, PHP 5)
atan — Arc 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.