root(a + b)
<math xmlns="http://www.w3.org/1998/Math/MathML"> <apply> <root/> <degree> <ci>n</ci> </degree> <apply> <plus/> <ci>a</ci> <ci>b</ci> </apply> </apply> </math>
Author: Design Science, Inc. (E. Cannon, E. Tabacman, R.Miner)