/usr/share/calc/help/atanh is in apcalc-common 2.12.4.4-3.
This file is owned by root:root, with mode 0o644.
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| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 | NAME
    atanh - inverse hyperbolic tangent
SYNOPSIS
    atanh(x [,eps])
TYPES
    x		real
    eps		nonzero real, defaults to epsilon()
    return	real
DESCRIPTION
    Returns the atanh of x to a multiple of eps with error less in
    absolute value than .75 * eps.
    atanh(x) is the real number v for which tanh(v) = x.  It is given by
		atanh(x) = ln((1 + x)/(1 - x))/2
EXAMPLE
    ; print atanh(.5,1e-5), atanh(.5,1e-10), atanh(.5,1e-15), atanh(.5,1e-20)
    .54931 .5493061443 .549306144334055 .5493061443340548457
LIMITS
    none
LINK LIBRARY
    NUMBER *qatanh(NUMBER *x, NUMBER *eps)
SEE ALSO
    asinh, acosh, asech, acsch, acoth, epsilon
## Copyright (C) 1999  Landon Curt Noll
##
## Calc is open software; you can redistribute it and/or modify it under
## the terms of the version 2.1 of the GNU Lesser General Public License
## as published by the Free Software Foundation.
##
## Calc is distributed in the hope that it will be useful, but WITHOUT
## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
## or FITNESS FOR A PARTICULAR PURPOSE.	 See the GNU Lesser General
## Public License for more details.
##
## A copy of version 2.1 of the GNU Lesser General Public License is
## distributed with calc under the filename COPYING-LGPL.  You should have
## received a copy with calc; if not, write to Free Software Foundation, Inc.
## 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
##
## @(#) $Revision: 30.1 $
## @(#) $Id: atanh,v 30.1 2007/03/16 11:10:42 chongo Exp $
## @(#) $Source: /usr/local/src/cmd/calc/help/RCS/atanh,v $
##
## Under source code control:	1994/03/19 01:40:27
## File existed as early as:	1994
##
## chongo <was here> /\oo/\	http://www.isthe.com/chongo/
## Share and enjoy!  :-)	http://www.isthe.com/chongo/tech/comp/calc/
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