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54 lines
1.6 KiB
Plaintext
54 lines
1.6 KiB
Plaintext
NAME
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sech - hyperbolic secant
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SYNOPSIS
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sech(x [,eps])
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TYPES
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x real
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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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Calculate the sech of x to the nearest or next to nearest multiple of
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epsilon, with absolute error less than .75 * abs(eps).
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sech(x) = 2/(exp(x) + exp(-x))
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EXAMPLE
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; print sech(1, 1e-5), sech(1, 1e-10), sech(1, 1e-15), sech(1, 1e-20)
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0.64805 0.6480542737 0.648054273663885 0.64805427366388539958
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LIMITS
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unlike sin and cos, x must be real
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eps > 0
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LINK LIBRARY
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NUMBER *qsech(NUMBER *x, NUMBER *eps)
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SEE ALSO
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sinh, cosh, tanh, csch, coth, epsilon
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## Copyright (C) 1999,2021 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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## 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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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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