ObjectPascal
ArcCos
Function
The Arc Cosine of a number, returned in radians Math unit
 function ArcCos ( const Number : Extended ) : Extended;
Description
The ArcCos function is a mathematical function giving the value in radians of the Arc Cosine of Number.
 
PI radians  = 180 degrees
Notes
The System unit supports only the following angular functions:

ArcTan
Sin
Cos


Special floating point values INF, -INF yield +PI/2 and -PI/2 respectively.
Related commands
ArcSin The Arc Sine of a number, returned in radians
ArcTan The Arc Tangent of a number, returned in radians
Cos The Cosine of a number
Sin The Sine of a number
Tan The Tangent of a number
 
Example code : The ArcCos of 0.5 gives 60 degrees
var
  float : single;
begin
  // The ArcCos of 0.5 should give 60 degrees
  float := ArcCos(0.5);
  float := RadToDeg(float);  // Convert result to degrees
  WriteLn('ArcCos of 0.5 = '+FloatToStr(float)+' degrees');
end;
Show full unit code
   ArcCos of 0.5 = 60 degrees