The two-argument atan2 function computes the arctangent of "y" / "x" given "y" and "x", but with a range of (−, ]. In other words, atan2("y", "x") is the angle between the positive "x"-axis of a plane and the point ("x", "y") on it, with positive sign for counter-clockwise angles (upper half-plane, "y" > 0), and negative sign for clockwise angles (lower half-plane, "y" < 0). It was first introduced in many computer programming languages, but it is now also common in other fields of science and engineering.