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Update section 17.3 (Trigonometry) of arith.txi Add text to help strings to indicate which functions use radians and which use degrees. Add cross-references to radian function descriptions.
author Rik <rdrider0-list@yahoo.com>
date Sun, 26 Apr 2009 22:19:57 -0700
parents a1dbe9d80eee
children 16f53d29049f
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1 ## Copyright (C) 2006, 2007 David Bateman
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2 ##
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3 ## This file is part of Octave.
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4 ##
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5 ## Octave is free software; you can redistribute it and/or modify it
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6 ## under the terms of the GNU General Public License as published by
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7 ## the Free Software Foundation; either version 3 of the License, or (at
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8 ## your option) any later version.
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9 ##
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10 ## Octave is distributed in the hope that it will be useful, but
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11 ## WITHOUT ANY WARRANTY; without even the implied warranty of
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12 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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13 ## General Public License for more details.
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14 ##
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15 ## You should have received a copy of the GNU General Public License
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16 ## along with Octave; see the file COPYING. If not, see
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17 ## <http://www.gnu.org/licenses/>.
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18
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19 ## -*- texinfo -*-
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20 ## @deftypefn {Function File} {} tand (@var{x})
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21 ## Compute the tangent for each element of @var{x} in degrees. Returns zero
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22 ## for elements where @code{@var{x}/180} is an integer and @code{Inf} for
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23 ## elements where @code{(@var{x}-90)/180} is an integer.
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24 ## @seealso{atand, tan}
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25 ## @end deftypefn
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26
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27 ## Author: David Bateman <dbateman@free.fr>
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28
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29 function y = tand (x)
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30 if (nargin != 1)
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31 print_usage ();
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32 endif
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33 I0 = x / 180;
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34 I90 = (x-90) / 180;
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35 y = tan (I0 .* pi);
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36 y(I0 == round (I0) & finite (I0)) = 0;
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37 y(I90 == round (I90) & finite (I90)) = Inf;
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38 endfunction;
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39
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40 %!error(tand())
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41 %!error(tand(1,2))
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42 %!assert(tand(10:10:80),tan(pi*[10:10:80]/180),-10*eps)
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43 %!assert(tand([0,180,360]) == 0)
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44 %!assert(tand([90,270]) == Inf)