<?xml version="1.0" encoding="utf-8"?>
<page xmlns="http://projectmallard.org/1.0/" type="guide" id="variable" xml:lang="zh_CN">

    <info>
        <link type="guide" xref="index#equation"/>
    </info>

	<title>变量</title>
    
    <p>
    To assign a value to a variable use the = symbol or choose the variable to assign to with the <gui>x</gui> button in <link xref="mouse">advanced mode</link>.
    A variable name must only contain upper or lower case characters.
    </p>
    <example>
    <p>x=5</p>
    <p>
    example=82
    </p>
    </example>
    <p>变量可以用在任何等式中，用来替代所赋数值。变量可以用 <gui>x</gui> 按钮插入。</p>
    <example>
    <p>6x+3</p>
    <p>xy−3x+7y−21</p>
    </example>
    <p>下面的变量是预定义好的。</p>
    <table>
    <tr>
    <td><p>_</p></td>
    <td><p>上次运算结果</p></td>
    </tr>
    <tr>
    <td><p>e</p></td>
    <td><p><link xref="logarithm">Euler's Number</link></p></td>
    </tr>
    <tr>
    <td><p>π</p></td>
    <td><p><link xref="trigonometry">Pi</link></p></td>
    </tr>
    <tr>
    <td><p>τ</p></td>
    <td><p><link xref="trigonometry">Tau</link></p></td>
    </tr>
    <tr>
    <td><p>rand</p></td>
    <td><p>在 [0,1] 之间的随机值(在每次读取时改变)</p></td>
    </tr>
    </table>
</page>
