The atan() function returns the arc tangent of arg as a numeric value between -Pi/2 and Pi/2 radians.
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.
Parameter | Description |
---|---|
arg | Required. Specifies an argument to process |
The arc tangent of arg in radians.