Reference for package '#rtl'

ArcTan2

Return arctangent of (y/x)

Declaration

Source position: math.pp line 361

  function ArcTan2(y: Float; x: Float) : Float;

Description

arctan2 calculates arctan(y/x), and returns an angle in the correct quadrant. The returned angle will be in the range $-\pi$ to $\pi$ radians. The values of x and y must be between -2\^{}64 and 2\^{}64, moreover x should be different from zero. On Intel systems this function is implemented with the native intel fpatan instruction.

See also

Name Description
arccos Return inverse cosine
arcosh Return inverse hyperbolic cosine
arsinh Return inverse hyperbolic sine
artanh Return inverse hyperbolic tangent

Example

Program Example6;
{ Program to demonstrate the arctan2 function. }
Uses math;
  Procedure WriteRadDeg(X : float);
  begin
    Writeln(X:8:5,' rad = ',radtodeg(x):8:5,' degrees.')
  end;
begin
  WriteRadDeg (arctan2(2,1));
end.