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TANH(3)                    Linux Programmer's Manual                   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():
           _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600 ||
           _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L;
           or cc -std=c99
DESCRIPTION
       The tanh() function returns 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.
CONFORMING TO
       C99, POSIX.1-2001.  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 3.53 of the Linux  man-pages  project.   A
       description  of  the project, and information about reporting bugs, can
       be found at http://www.kernel.org/doc/man-pages/.

                                  2010-09-20                           TANH(3)