tanh(3)

NAME

   tanh, tanhf, tanhl - hyperbolic tangent function

SYNOPSIS

   #include <math.h>

   double tanh(double x);
   float tanhf(float x);
   long double tanhl(long double x);

   Link with -lm.

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

   tanhf(), tanhl():
       _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
           || /* Since glibc 2.19: */ _DEFAULT_SOURCE
           || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

DESCRIPTION

   These  functions  return  the hyperbolic tangent of x, which is defined
   mathematically as:

       tanh(x) = sinh(x) / cosh(x)

RETURN VALUE

   On success, these functions return the hyperbolic tangent of x.

   If x is a NaN, a NaN is returned.

   If x is +0 (-0), +0 (-0) is returned.

   If x is positive infinity (negative infinity), +1 (-1) is returned.

ERRORS

   No errors occur.

ATTRIBUTES

   For  an  explanation  of  the  terms  used   in   this   section,   see
   attributes(7).

   
   Interface                 Attribute      Value   
   
   tanh(), tanhf(), tanhl()  Thread safety  MT-Safe 
   

CONFORMING TO

   C99, POSIX.1-2001, POSIX.1-2008.

   The variant returning double also conforms to SVr4, 4.3BSD, C89.

SEE ALSO

   acosh(3), asinh(3), atanh(3), cosh(3), ctanh(3), sinh(3)

COLOPHON

   This  page  is  part of release 4.09 of the Linux man-pages project.  A
   description of the project, information about reporting bugs,  and  the
   latest     version     of     this    page,    can    be    found    at
   https://www.kernel.org/doc/man-pages/.

                              2016-03-15                           TANH(3)

---

Free and Open Source Software