@c ----------------------------------------------------------------------
@node tan, math
@subheading Syntax

@example
#include <math.h>

double tan(double x);
@end example

@subheading Description

This function computes the tangent of @var{x} (which should be given in
radians).

@subheading Return Value

The tangent of @var{x}.  If the absolute value of @var{x} is finite but
greater than or equal to @math{2^63}, the return value is 0 (since for
arguments that large each bit of the mantissa is more than @code{Pi}).
If the value of @var{x} is infinite or @code{NaN}, the return value is
@code{NaN} and @code{errno} is set to @code{EDOM}.

@subheading Portability

@portability ansi, posix