ArcTan

The ArcTan function is a mathematical function giving the value in radians of the Arc Tangent of Number.

PI radians = 180 degrees

Example:

var
  floatValue : single;

const
  PI = 3.14;

begin
  // The ArcTan of PI/2 should give 1.0
  floatValue := ArcTan(PI/2);
  ShowMessage('ArcTan of PI/2 = '+FloatToStr(floatValue));
end;