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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; 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 3.24 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/.

                                  2008-08-05                           TANH(3)