arctan1

arctan(a + b)

W3C sample	WIRIS
	$a b$

<math xmlns="http://www.w3.org/1998/Math/MathML">
  <apply>
    <arctan/>
    <apply>
      <plus/>
      <ci>a</ci>
      <ci>b</ci>
    </apply>
  </apply>
</math>

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