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64 lines
2.0 KiB
Plaintext
64 lines
2.0 KiB
Plaintext
NAME
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atan2 - angle to point
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SYNOPSIS
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atan2(y, x, [,eps])
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TYPES
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y real
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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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If x and y are not both zero, atan2(y, x, eps) returns, as a multiple of
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eps with error less than abs(eps), the angle t such that
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-pi < t <= pi and x = r * cos(t), y = r * sin(t), where
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r > 0. Usually the error does not exceed abs(eps)/2.
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Note that by convention, y is the first argument; if x > 0,
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atan2(y, x) = atan(y/x).
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To conform to the 4.3BSD ANSI/IEEE 754-1985 math lib, atan2(0,0)
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returns 0.
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EXAMPLE
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; print atan2(0,0), atan2(1,sqrt(3)), atan2(17,53,1e-100)
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0 ~.52359877559829887307 ~.31038740713235146535
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LIMITS
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none
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LINK LIBRARY
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NUMBER *qatan2(NUMBER *y, *x, *acc)
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SEE ALSO
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acos, asin, atan, cos, epsilon, sin, tan
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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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## 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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##
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## @(#) $Revision: 30.1 $
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## @(#) $Id: atan2,v 30.1 2007/03/16 11:10:42 chongo Exp $
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## @(#) $Source: /usr/local/src/bin/calc/help/RCS/atan2,v $
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##
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## Under source code control: 1994/03/19 01:40:26
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## File existed as early as: 1994
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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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