
acos(+Number, -Result)

   Evaluates the trigonometric function acos(Number) and unifies the resulting
value with Result.



Arguments
   Number              A number.
   Result              Output: float.

Type
   Arithmetic

Description
   This predicate is used by the ECLiPSe compiler to expand evaluable
   arithmetic expressions.  So the call to acos(Number, Result) is
   equivalent to

    Result is acos(Number)

   which should be preferred for portability.

   In coroutining mode, if Number is uninstantiated, the call to acos/2 is
   delayed until this variable is instantiated.


Modes and Determinism
   acos(+, -) is det

Exceptions
     4 --- Number is not instantiated (non-coroutining mode only).
    24 --- Number is not of a numeric type.
    20 --- Illegal arithmetic operation: Number is greater than 1 or less than -1.
   141 --- Argument is of type breal

Examples
   
Success:
    Result is acos(1.0).	% gives Result = 0.0).
    Result is acos(-0.5).	% gives Result = 2.0944
    Result is acos(0).		% gives Result = 1.5708

Error:
    Result is acos(2.0).	% arithmetic exception


See Also
   is / 2
