<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
  <mrow>
    <msub>
      <mi>x</mi>
      <mrow>
        <mi>N</mi>
        <mo>+</mo>
        <mn>1</mn>
      </mrow>
    </msub>
    <mspace width="1em"/>
    <mo>=</mo>
    <mspace width="1em"/>
    <msub>
      <mi>x</mi>
      <mi>N</mi>
    </msub>
    <mo>&#x2212;</mo>
    <mfrac>
      <mrow>
        <mn>2</mn>
        <mi>f</mi>
        <mfenced>
          <mrow>
            <mi>x</mi>
          </mrow>
        </mfenced>
        <mi>f</mi>
        <mo>&#x2032;</mo>
        <mfenced>
          <mrow>
            <mi>x</mi>
          </mrow>
        </mfenced>
      </mrow>
      <mrow>
        <mn>2</mn>
        <msup>
          <mfenced>
            <mrow>
              <mi>f</mi>
              <mo>&#x2032;</mo>
              <mfenced>
                <mrow>
                  <mi>x</mi>
                </mrow>
              </mfenced>
            </mrow>
          </mfenced>
          <mn>2</mn>
        </msup>
        <mo>&#x2212;</mo>
        <mi>f</mi>
        <mfenced>
          <mrow>
            <mi>x</mi>
          </mrow>
        </mfenced>
        <mi>f</mi>
        <mo>&#x2033;</mo>
        <mfenced>
          <mrow>
            <mi>x</mi>
          </mrow>
        </mfenced>
      </mrow>
    </mfrac>
  </mrow>
</math>

