TANH

Section: Linux Programmer's Manual (3)
Updated: 2008-08-05
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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.

COLOPHON

This page is part of release 3.22 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/.