rec-apply4

Test of use of functions as arguments to other operators.

W3C sample	WIRIS
[N/A]	$minus tan cos x$

<math xmlns="http://www.w3.org/1998/Math/MathML">
  <apply>
    <apply>
      <csymbol cd="arith1">minus</csymbol>
      <csymbol cd="transc1">tan</csymbol>
      <csymbol cd="transc1">cos</csymbol>
    </apply>
    <ci>x</ci>
  </apply>
</math>

Author: Design Science, Inc (D. Doyle, R. Miner)