NAME
tanh(), tanhf() — hyperbolic tangent functions
SYNOPSIS
#include <math.h>
double tanh(double x);
float tanhf(float x);
DESCRIPTION
The
tanh()
function returns the hyperbolic tangent of its argument.
tanhf()
is a
float
version of
tanh();
it takes a
float
argument and returns a
float
result.
To use this function, compile either with the default
-Ae
option or with the
-Aa
and
-D_HPUX_SOURCE
options.
tanhf()
is not specified by any standard, but it is named in accordance with
the conventions specified in the "Future Library Directions" section
of the ANSI C standard.
To use these functions, make sure your program includes
<math.h>,
and link in the math library by specifying
-lm
on the compiler or linker command line.
RETURN VALUE
If
x
is ±INFINITY,
tanh()
returns ±1.0 respectively.
If
x
is NaN,
tanh()
returns NaN.
If the correct value after rounding would be smaller in magnitude than
MINDOUBLE,
tanh()
returns zero.
ERRORS
No errors are defined.
STANDARDS CONFORMANCE
tanh(): SVID3, XPG4.2, ANSI C
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