<math xmlns="http://www.w3.org/1998/Math/MathML">
<apply>
<partialdiff/>
<bvar>
<ci>x</ci>
<degree>
<ci>n</ci>
</degree>
</bvar>
<bvar>
<ci>y</ci>
<degree>
<ci>m</ci>
</degree>
</bvar>
<apply>
<sin/>
<apply>
<times/>
<ci>x</ci>
<ci>y</ci>
</apply>
</apply>
</apply>
</math>
Author: MathML 2 Recommendation