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

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



Arguments
   Number              A number.
   Result              Output: float or breal.

Type
   Arithmetic

Description

   Evaluates the trigonometric function atan(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 atan/2 is
   delayed until this variable is instantiated.




Modes and Determinism
   atan(+, -) is det

Exceptions
     4 --- Number is not instantiated (non-coroutining mode only).
    24 --- Number is not of a numeric type.

Examples
   
    Result is atan(0.0).		% gives Result = 0.0
    Result is atan(1.0).		% gives Result = 0.785398
    Result is atan(-8).			% gives Result = -1.44644


See Also
   is / 2
