scilab/modules/elementary_functions/help/en_US/trigonometry/cotd.xml

   1 <?xml version="1.0" encoding="UTF-8"?>
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  16 <refentry xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink"
  17           xmlns:svg="http://www.w3.org/2000/svg" xmlns:ns5="http://www.w3.org/1999/xhtml"
  18           xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:db="http://docbook.org/ns/docbook"
  19           xmlns:scilab="http://www.scilab.org"  xml:id="cotd" xml:lang="en">
  20     <refnamediv>
  21         <refname>cotd</refname>
  22         <refpurpose>element-wise cotangent function, argument in degree</refpurpose>
  23     </refnamediv>
  24     <refsynopsisdiv>
  25         <title>Syntax</title>
  26         <synopsis>y = cotd(x)</synopsis>
  27     </refsynopsisdiv>
  28     <refsection>
  29         <title>Arguments</title>
  30         <variablelist>
  31             <varlistentry>
  32                 <term>x</term>
  33                 <listitem>
  34                     <para>a real array.</para>
  35                 </listitem>
  36             </varlistentry>
  37             <varlistentry>
  38                 <term>y</term>
  39                 <listitem>
  40                     <para>a real array with same dimensions as
  41                         <varname>x</varname>.
  42                     </para>
  43                 </listitem>
  44             </varlistentry>
  45         </variablelist>
  46     </refsection>
  47     <refsection>
  48         <title>Description</title>
  49         <para>
  50             The entries of <varname>y</varname> are the cotangents of the
  51             corresponding entries of <varname>x</varname> supposed to be given in
  52             degree. <code>t=cos(x)./sin(x)</code>. For entries equal to
  53             <literal>n*180</literal> with <literal>n</literal> integer, the results
  54             are infinite, whereas <code>cotg(n*%pi)</code> is large but finite
  55             because <constant>%pi</constant> cannot be represented exactly. For entries
  56             equal to <literal>n*90</literal> with <literal>n</literal> integers and
  57             odd the results are exactly <literal>0</literal>.
  58         </para>
  59     </refsection>
  60     <refsection>
  61         <title>Examples</title>
  62         <programlisting role="example"><![CDATA[
  63 cotd([30 45 60 90])
  64 cotd([-180 -90 0 90 180])
  65  ]]></programlisting>
  66     <screen><![CDATA[
  67 --> cotd([30 45 60 90])
  68  ans  =
  69    1.7320508   1.   0.5773503   0.
  70
  71 --> cotd([-180 -90 0 90 180])
  72  ans  =
  73    Inf   0.   Inf   0.   Inf
  74 ]]></screen>
  75     </refsection>
  76     <refsection role="see also">
  77         <title>See also</title>
  78         <simplelist type="inline">
  79             <member>
  80                 <link linkend="cotg">cotg</link>
  81             </member>
  82             <member>
  83                 <link linkend="coth">coth</link>
  84             </member>
  85             <member>
  86                 <link linkend="tan">tan</link>
  87             </member>
  88             <member>
  89                 <link linkend="tand">tand</link>
  90             </member>
  91         </simplelist>
  92     </refsection>
  93 </refentry>