ATANH(3)               FreeBSD Library Functions Manual               ATANH(3)

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.

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

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

FreeBSD 13.1-RELEASE-p6          June 9, 2013          FreeBSD 13.1-RELEASE-p6