ATANH(3) MachTen Programmer’s Manual ATANH(3)

NAME
atanh - inverse hyperbolic tangent function

SYNOPSIS
#include <math.h>

double
atanh(double x)

DESCRIPTION
The atanh() function computes the inverse hyperbolic tangent of the real
argument x. For a discussion of error due to roundoff, see math(3).

RETURN VALUES
The atanh() function returns the inverse hyperbolic tangent of x if suc-
cessful. On the VAX and Tahoe, if the argument has absolute value bigger
than or equal to 1, atanh() sets the global variable errno to EDOM and a
reserved operand fault is generated.

SEE ALSO
acosh(3), asinh(3), exp(3), infnan(3) math(3),

HISTORY
The atanh() function appeared in 4.3BSD.

4.3 Berkeley Distribution June 4, 1993 1