示例：误差函数

1. 使用 erf 函数来绘制不同 x 值时的误差函数图像。

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            <plotEquation>
              <math resultRef="93">
                <id xml:space="preserve" xmlns="http://schemas.mathsoft.com/math50">x</id>
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              <math resultRef="94">
                <placeholder xmlns="http://schemas.mathsoft.com/math50" />
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        <yAxis rank="1" legend-position="PlotBoundaryLeft" start="-1.5" end="2">
          <axisLine position="origin" positionticmark="5" legendWidth="96.62" />
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            <gridFrequency>8</gridFrequency>
            <gridLabels display="true" />
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            <tickMarks display="true" />
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          <axisLabel />
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          <plotEquations>
            <plotEquation>
              <math resultRef="101">
                <apply xmlns="http://schemas.mathsoft.com/math50">
                  <id xml:space="preserve">erf</id>
                  <id xml:space="preserve">x</id>
                </apply>
              </math>
              <math resultRef="102">
                <placeholder xmlns="http://schemas.mathsoft.com/math50" />
              </math>
            </plotEquation>
          </plotEquations>
          <xyDomain scale-type="linear" auto-scale="true">
            <startValue resultRef="96">
              <real xmlns="http://schemas.mathsoft.com/math50">-1.5</real>
            </startValue>
            <secondTickValue resultRef="98">
              <real xmlns="http://schemas.mathsoft.com/math50">-1.0</real>
            </secondTickValue>
            <endValue resultRef="100">
              <real xmlns="http://schemas.mathsoft.com/math50">2.0</real>
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函数 erf 关于直线 y=0 对称。

2. 使用 erfc 函数来绘制不同 x 值时的互补误差函数图像。

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        <xAxis rank="1" legend-position="PlotBoundaryBottom" start="-5" end="5">
          <axisLine position="ticknumberlock" positionticmark="3" legendWidth="60.93" />
          <axisGrid>
            <gridFrequency>11</gridFrequency>
            <gridLabels display="true" />
            <gridLines />
            <tickMarks display="true" />
          </axisGrid>
          <axisLabel />
          <markers />
          <plotEquations>
            <plotEquation>
              <math resultRef="111">
                <id xml:space="preserve" xmlns="http://schemas.mathsoft.com/math50">x</id>
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                <placeholder xmlns="http://schemas.mathsoft.com/math50" />
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        </xAxis>
        <yAxis rank="1" legend-position="PlotBoundaryLeft" start="-1.5" end="2">
          <axisLine position="origin" positionticmark="5" legendWidth="103.526666666667" />
          <axisGrid>
            <gridFrequency>8</gridFrequency>
            <gridLabels display="true" />
            <gridLines />
            <tickMarks display="true" />
          </axisGrid>
          <axisLabel />
          <markers>
            <marker resultRef="113" display="true" color="#FF2E3192" line-style="Dash" value="1">
              <real xmlns="http://schemas.mathsoft.com/math50">1</real>
            </marker>
          </markers>
          <plotEquations>
            <plotEquation>
              <math resultRef="121">
                <apply xmlns="http://schemas.mathsoft.com/math50">
                  <id xml:space="preserve">erfc</id>
                  <id xml:space="preserve">x</id>
                </apply>
              </math>
              <math resultRef="122">
                <placeholder xmlns="http://schemas.mathsoft.com/math50" />
              </math>
            </plotEquation>
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          <xyDomain scale-type="linear" auto-scale="true">
            <startValue resultRef="116">
              <real xmlns="http://schemas.mathsoft.com/math50">-1.5</real>
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            <secondTickValue resultRef="118">
              <real xmlns="http://schemas.mathsoft.com/math50">-1.0</real>
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            <endValue resultRef="120">
              <real xmlns="http://schemas.mathsoft.com/math50">2.0</real>
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        </yAxis>
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函数 erfc 关于直线 y=1.0 对称。

3. 创建图像来显示在不同 x 值时 erf 和 erfc 函数之间的关系。

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            <gridLabels display="true" />
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            <tickMarks display="true" />
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          <axisLabel />
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          <plotEquations>
            <plotEquation>
              <math resultRef="133">
                <id xml:space="preserve" xmlns="http://schemas.mathsoft.com/math50">x</id>
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        </xAxis>
        <yAxis rank="1" legend-position="PlotBoundaryLeft" start="-1.5" end="2">
          <axisLine position="origin" positionticmark="5" legendWidth="103.526666666667" />
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            <gridFrequency>8</gridFrequency>
            <gridLabels display="true" />
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            <tickMarks display="true" />
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          <axisLabel />
          <markers>
            <marker resultRef="135" display="true" color="#FF2E3192" line-style="Dash" value="0.5">
              <real xmlns="http://schemas.mathsoft.com/math50">0.5</real>
            </marker>
          </markers>
          <plotEquations>
            <plotEquation>
              <math resultRef="143">
                <apply xmlns="http://schemas.mathsoft.com/math50">
                  <id xml:space="preserve">erf</id>
                  <id xml:space="preserve">x</id>
                </apply>
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              <math resultRef="144">
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            <plotEquation>
              <math resultRef="145">
                <apply xmlns="http://schemas.mathsoft.com/math50">
                  <id xml:space="preserve">erfc</id>
                  <id xml:space="preserve">x</id>
                </apply>
              </math>
              <math resultRef="146">
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              </math>
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            <endValue resultRef="142">
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        </yAxis>
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此函数关于直线 y=0.5 对称。

4. 创建绘图来显示在不同 x 值时的 erfc(x)=1-erf(x)。

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            <gridLabels display="true" />
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            <tickMarks display="true" />
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          <axisLabel />
          <markers />
          <plotEquations>
            <plotEquation>
              <math resultRef="159">
                <id xml:space="preserve" xmlns="http://schemas.mathsoft.com/math50">x</id>
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              <math resultRef="167">
                <apply xmlns="http://schemas.mathsoft.com/math50">
                  <minus />
                  <real>1</real>
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                    <id xml:space="preserve">erf</id>
                    <id xml:space="preserve">x</id>
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                </apply>
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              <math resultRef="168">
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            <plotEquation>
              <math resultRef="169">
                <apply xmlns="http://schemas.mathsoft.com/math50">
                  <id xml:space="preserve">erfc</id>
                  <id xml:space="preserve">x</id>
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