
acos(+Number, -Result)
-Result is acos(+Number)

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



Arguments
   Number              A number.
   Result              Output: float.

Type
   Arithmetic

Description

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

   This predicate can be used as a function in arithmetic expressions.
   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
