(PHP 4, PHP 5)
atan2 — Arc tangent of two variables
$y
, float $x
)
This function calculates the arc tangent of the two variables
x and y. It is
similar to calculating the arc tangent of
y / x, except that
the signs of both arguments are used to determine the quadrant of
the result.
The function returns the result in radians, which is between -PI and PI (inclusive).
y
Dividend parameter
x
Divisor parameter
The arc tangent of y/x
in radians.