# tanh(3) [netbsd man page]

```TANH(3) 						   BSD Library Functions Manual 						   TANH(3)

NAME
tanh, tanhf -- hyperbolic tangent function

LIBRARY
Math Library (libm, -lm)

SYNOPSIS
#include <math.h>

double
tanh(double x);

float
tanhf(float x);

DESCRIPTION
The tanh() and tanhf() functions compute the hyperbolic tangent of x.  For a discussion of error due to roundoff, see math(3).

RETURN VALUES
Upon successful completion, these functions return the hyperbolic tangent value.  The following may also occur:

1.	If x is +- 0, x is returned.

2.	If x is NaN, a NaN is returned.

3.	If x is positive infinity, a value 1 is returned; if x is negative infinity, -1 is returned.

4.	If x is subnormal, a range error can occur and x is returned.

acos(3), asin(3), atan(3), atan2(3), cos(3), cosh(3), math(3), sin(3), sinh(3), tan(3)

STANDARDS
The described functions conform to ISO/IEC 9899:1999 (``ISO C99'').

BSD								September 18, 2011							       BSD```

## Check Out this Related Man Page

```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);

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.