NAME

atanh, atanhf, atanhl —

inverse hyperbolic tangent functions

LIBRARY

Math Library (libm, -lm)

SYNOPSIS

#include <math.h>

double
atanh(double x);

float
atanhf(float x);

long double
atanhl(long double x);

DESCRIPTION

The atanh(), atanhf(), and atanhl() functions compute the inverse hyperbolic tangent of the real argument x. For a discussion of error due to roundoff, see math(3).

RETURN VALUES

These functions return the inverse hyperbolic tangent of x if successful. If the argument has absolute value 1, a divide-by-zero exception is raised and an infinity is returned. If |x| > 1, an invalid exception is raised and an NaN is returned.

HISTORY

The atanh(), atanhf(), and atanhl() functions appeared in 4.3BSD, FreeBSD 2.0, and FreeBSD 10.0, respectively.