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comparison doc/interpreter/arith.txi @ 15443:0b6c29cb53d0

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Update trig function doc
author Michael Godfrey <michaeldgodfrey@gmail.com>
date Tue, 25 Sep 2012 21:53:44 -0400
parents 5984aa619cd9
children 46dd555edd33
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15442:015cc3d1f389 15443:0b6c29cb53d0
116 which work directly on an argument specified in degrees. These functions 116 which work directly on an argument specified in degrees. These functions
117 are named after the base trigonometric function with a @samp{d} suffix. For 117 are named after the base trigonometric function with a @samp{d} suffix. For
118 example, @code{sin} expects an angle in radians while @code{sind} expects an 118 example, @code{sin} expects an angle in radians while @code{sind} expects an
119 angle in degrees. 119 angle in degrees.
120 120
121 Octave uses the C library trigonometric functions. It is expected that these
122 functions are defined by the ISO/IEC 9899 standard. This Standard is available
123 at: http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1124.pdf. Section F.9.1 deals
124 with the trigonometric functions. The behavior of most of the functions is
125 relatively straightforward. However, there are some exceptions to the standard
126 behavior. Many of the exceptions involve the behavior for -0.
127 The most complex case is atan2. Octave exactly implements the behavior given
128 in the Standard. Including @tex $atan2(\pm0, -0)$ @end tex @ifnottex @code
129 {atan2(+- 0, 0)} @end ifnottex
130 returns @tex $\pm \pi.$@end tex @ifnottex @code{+- pi}.
131
132 It should be noted that Matlab uses different definitions which apparently
133 do not distinguish -0.
134
121 @DOCSTRING(sin) 135 @DOCSTRING(sin)
122 @DOCSTRING(cos) 136 @DOCSTRING(cos)
123 @DOCSTRING(tan) 137 @DOCSTRING(tan)
124 @DOCSTRING(sec) 138 @DOCSTRING(sec)
125 @DOCSTRING(csc) 139 @DOCSTRING(csc)