[Overview][Constants][Types][Classes][Procedures and functions][Index] | Reference for unit 'math' (#rtl)

# arccos

Return inverse cosine

## Declaration

Source position: math.pp line 280

`function arccos(`
`x: float`
`):float;`

## Description

Arccos returns the inverse cosine of its argument x. The argument x should lie between -1 and 1 (borders included).

## Errors

If the argument x is not in the allowed range, an EInvalidArgument exception is raised.

## See also

arcsin |  | Return inverse sine
arcosh |  | Return inverse hyperbolic cosine
arsinh |  | Return inverse hyperbolic sine
artanh |  | Return inverse hyperbolic tangent

## Example

    Program Example1;

    { Program to demonstrate the arccos function. }

    Uses math;

      Procedure WriteRadDeg(X : float);

      begin
        Writeln(X:8:5,' rad = ',radtodeg(x):8:5,' degrees.')
      end;

    begin
      WriteRadDeg (arccos(1));
      WriteRadDeg (arccos(sqrt(3)/2));
      WriteRadDeg (arccos(sqrt(2)/2));
      WriteRadDeg (arccos(1/2));
      WriteRadDeg (arccos(0));
      WriteRadDeg (arccos(-1));
    end.

Documentation generated on: Feb 26 2014