atan

atan - Arc tangent

float atan ( float $x )

Returns the arc tangent of x 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:

x - The argument to process. It can be a scalar or an array.

Return Value:

The arc tangent of x in radians. If x is an array, the return value will also be an array.

Version

1.0 and above.