Returns the tangent of the argument. The argument is an angle in radians.
math:tan( $θ as xs:double?xs:double?If $
θ is the empty sequence, the function returns the empty
sequence.
Otherwise the result is the tangent of $
θ (which is treated as an angle
in radians) as defined in the specification of the
tan function applied to 64-bit binary floating point values.
The expression math:tan(()) returns ().
The expression math:tan(0) returns 0.0e0.
The expression math:tan(-0.0e0) returns -0.0e0.
The expression math:tan(math:pi() div 4) returns 1.0e0.
The expression math:tan(-math:pi() div 4) returns -1.0e0.
The expression 1 div math:tan(math:pi() div 2) returns 0.0e0.
The expression 1 div math:tan(-math:pi() div 2) returns -0.0e0.
The expression math:tan(math:pi()) returns 0.0e0.
The expression math:tan(xs:double('NaN')) returns xs:double('NaN').
The expression math:tan(xs:double('INF')) returns xs:double('NaN').
The expression math:tan(xs:double('-INF')) returns xs:double('NaN').
The treatment of the invalidOperation and underflow exceptions
is defined in .
If $
θ is positive or negative infinity, or NaN,
then the result is NaN.
