May 2, 1991 TANH 3

### NAME

tanh, tanhf - hyperbolic tangent function

### LIBRARY

Math Library (libm, -lm)

### SYNOPSIS

```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

The tanh(``) function returns the hyperbolic tangent value.

### SEE ALSO

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

### STANDARDS

The tanh(``) function conforms to ANSI X3.159-1989 (``ANSI C89'') .