(a + b) / (a - b)
<math xmlns="http://www.w3.org/1998/Math/MathML"> <apply> <csymbol cd="arith1">divide</csymbol> <apply> <csymbol cd="arith1">plus</csymbol> <ci>a</ci> <ci>b</ci> </apply> <apply> <csymbol cd="arith1">minus</csymbol> <ci>a</ci> <ci>b</ci> </apply> </apply> </math>
Author: Design Science, Inc. (E. Cannon, E. Tabacman, R.Miner)