TANH(3) BSD Programmer's Manual TANH(3)

**tanh**, **tanhf** - hyperbolic tangent function

libm

**#include <math.h>**
*double*
**tanh**(*double x*);
*float*
**tanhf**(*float x*);

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

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)

The described functions conform to ISO/IEC 9899:1999 ("ISO C99").
MirBSD #10-current September 18, 2011 1