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tan(+Number, -Result)

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

Description

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

Exceptions

(4) instantiation fault
Number is not instantiated (non-coroutining mode only).
(24) number expected
Number is not of a numeric type.
(20) arithmetic exception
Illegal arithmetic operation: Number is (2k +1) * pi/2 for every integer k.

Examples

Success:
    Result is tan(0).		% gives Result = 0.0
    Result is tan(12.3).        % gives Result = -0.272854
    Result is tan(-1).          % gives Result = -1.55741

Error:
    X is pi/2, tan(X). 		% arithmetic exception

See Also

is / 2