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tan(+Number, -Result)

Evaluates the trigonometric function tan(Number) and unifies the resulting value with Result.
A number.
A variable, float or breal.


This predicate is used by the ECLiPSe compiler to expand evaluable arithmetic expressions. So the call to tan(Number, Result) is equivalent to
    Result is tan(Number)
which should be preferred for portability.

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

Modes and Determinism


(4) instantiation fault
Number is not instantiated (non-coroutining mode only).
(5) type error
Result is a number but not a float or breal.
(24) number expected
Number is not of a numeric type.
(24) number expected
Result is neither a number nor a variable.
(20) arithmetic exception
Illegal arithmetic operation: Number is (2k +1) * pi/2 for every integer k.


      tan(0, 0.0).
      tan(12.3, Result).      (gives Result = -0.272854)
      tan(-1, Result).        (gives Result = -1.55741)
      tan(1, 0.0).
      tan(A, 6.0).                      (Error 4).
      tan(0, 0).                        (Error 5).
      X is pi/2, tan(X, Result).        (Error 20).
      tan(10.3 + 2, -0.272854).         (Error 24).
      tan(5, r).                        (Error 24).

See Also

is / 2