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59 lines
1.8 KiB
Plaintext
59 lines
1.8 KiB
Plaintext
NAME
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asech - inverse hyperbolic secant
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SYNOPSIS
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asech(x [,eps])
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TYPES
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x real, 0 < x <= 1
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eps nonzero real, defaults to epsilon()
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return real
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DESCRIPTION
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Returns the asech of x to a multiple of eps with error less in
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absolute value than .75 * eps.
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asech(x) is the real number v for which sech(v) = x. It is given by
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asech(x) = ln((1 + sqrt(1 - x^2))/x)
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EXAMPLE
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> print asech(.5,1e-5), asech(.5,1e-10), asech(.5,1e-15), asech(.5,1e-20)
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1.31696 1.3169578969 1.316957896924817 1.31695789692481670862
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LIMITS
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none
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LINK LIBRARY
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NUMBER *qasech(NUMBER *x, NUMBER *eps)
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SEE ALSO
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asinh, acosh, atanh, acsch, acoth, epsilon
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## Copyright (C) 1999 Landon Curt Noll
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##
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## Calc is open software; you can redistribute it and/or modify it under
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## the terms of the version 2.1 of the GNU Lesser General Public License
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## as published by the Free Software Foundation.
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##
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## Calc is distributed in the hope that it will be useful, but WITHOUT
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## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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## or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General
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## Public License for more details.
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##
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## A copy of version 2.1 of the GNU Lesser General Public License is
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## distributed with calc under the filename COPYING-LGPL. You should have
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## received a copy with calc; if not, write to Free Software Foundation, Inc.
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## 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
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##
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## @(#) $Revision: 29.2 $
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## @(#) $Id: asech,v 29.2 2000/06/07 14:02:33 chongo Exp $
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## @(#) $Source: /usr/local/src/cmd/calc/help/RCS/asech,v $
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##
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## Under source code control: 1995/11/13 03:49:00
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## File existed as early as: 1995
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##
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## chongo <was here> /\oo/\ http://www.isthe.com/chongo/
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## Share and enjoy! :-) http://www.isthe.com/chongo/tech/comp/calc/
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