tripleint1

<math xmlns="http://www.w3.org/1998/Math/MathML">
  <msubsup>
    <mo>&#x222D;</mo>
    <mn>0</mn>
    <mn>1</mn>
  </msubsup>
  <mi>f</mi>
  <mrow>
    <mo>(</mo>
    <mi>x</mi>
    <mo>)</mo>
  </mrow>
  <mtext>&#x200A;</mtext>
  <mo>&#x2146;</mo>
  <mi>x</mi>
</math>

Author: Design Science, Inc. (E. Cannon, E. Tabacman, R.Miner)