Node: ArcCos, Next: ArcSin, Previous: Append, Up: Reference

### ArcCos

#### Synopsis

         function ArcCos (x: Real): Real;

or

         function ArcCos (z: Complex): Complex;

#### Description

`ArcCos` returns the (principal value of the) arcus cosine of the argument. The result is in the range `0 < ArcCos (x) < Pi` for real arguments.

#### Conforming to

`ArcCos` is a GNU Pascal extension.

#### Example

         program ArcCosDemo;
         begin
           { yields 3.14159 as ArcCos (0.5) = Pi / 3 }
           WriteLn (3 * ArcCos (0.5) : 0 : 5)
         end.

#### See also

ArcSin, ArcTan, Sin, Cos, Ln, Arg.