<?xml version="1.0" encoding="UTF-8"?>
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<refentry xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink"
          xmlns:svg="http://www.w3.org/2000/svg" xmlns:ns5="http://www.w3.org/1999/xhtml"
          xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:db="http://docbook.org/ns/docbook"
          xmlns:scilab="http://www.scilab.org"  xml:id="asin" xml:lang="ja">
    <refnamediv>
        <refname>asin</refname>
        <refpurpose>逆正弦</refpurpose>
    </refnamediv>
    <refsynopsisdiv>
        <title>呼び出し手順</title>
        <synopsis>t = asin(x)</synopsis>
    </refsynopsisdiv>
    <refsection>
        <title>引数</title>
        <variablelist>
            <varlistentry>
                <term>x, t</term>
                <listitem>
                    <para>実数または複素数のベクトル，行列，超行列で，大きさは同じである.</para>
                </listitem>
            </varlistentry>
        </variablelist>
    </refsection>
    <refsection>
        <title>説明</title>
        <para>
            <varname>t</varname> のエントリは,
            <varname>x</varname>の対応するエントリの逆正弦となります.
        </para>
    </refsection>
    <refsection>
        <title>例</title>
        <scilab:image>
            xr = -1:0.05:1;
            subplot(1,2,1)
            plot(xr, real(asin(xr)))
            xtitle("x ∈[-1, 1], asin(x) ∈ ℝ", "x","")

            subplot(1,2,2)
            x = -2.5:.05:2.5;
            y = asin(x);
            plot(x,real(y),"k", x, imag(y));
            gce().children(1).foreground = color("orange");
            xtitle(".                             asin(x) ∈ ℂ","x","asin(x)")
            legend(["Real part", "Imaginary part"],-5)
            gca().tight_limits(1) = "on";

            gcf().children.grid = [1 1]*color("grey75")
            gcf().axes_size = [700, 370]
        </scilab:image>
        <programlisting role="example"><![CDATA[
x = 0:0.2:1; x = [-x ; x]
asin(x)

A = [1,2 ; 3,4];
a = asin(A)
sin(a)
 ]]></programlisting>
    <screen><![CDATA[
--> x = 0:0.2:1; x = [-x ; x]
 x  =
   0.  -0.2  -0.4  -0.6  -0.8  -1.
   0.   0.2   0.4   0.6   0.8   1.

--> asin(x)
 ans  =
   0.  -0.2013579  -0.4115168  -0.6435011  -0.9272952  -1.5707963
   0.   0.2013579   0.4115168   0.6435011   0.9272952   1.5707963


--> A = [1,2 ; 3,4];
--> a = asin(A)
 a  =
   1.5707963 + 0.i          1.5707963 - 1.3169579i
   1.5707963 - 1.7627472i   1.5707963 - 2.0634371i

--> sin(a)
 ans  =
   1. + 0.i          2. - 1.061D-16i
   3. - 1.732D-16i   4. - 2.372D-16i
]]></screen>
    </refsection>
    <refsection role="see also">
        <title>参照</title>
        <simplelist type="inline">
            <member>
                <link linkend="asind">asind</link>
            </member>
            <member>
                <link linkend="sind">sind</link>
            </member>
            <member>
                <link linkend="sin">sin</link>
            </member>
            <member>
                <link linkend="sinm">sinm</link>
            </member>
            <member>
                <link linkend="asinm">asinm</link>
            </member>
        </simplelist>
    </refsection>
    <refsection role="history">
        <title>履歴</title>
        <revhistory>
            <revision>
                <revnumber>5.5.2</revnumber>
                <revdescription>
                    For <literal>x>1</literal>, <literal>imag(asin(x))</literal> is now set negative.
                </revdescription>
            </revision>
        </revhistory>
    </refsection>
</refentry>