This draws a square root sign around the contents, for example the square root of 1 + x is expressed as:

<SQRT>1 + x</SQRT>

and possibly rendered as:
*(this is the best I can do with ascii art!)*

---------- / 1 + x v

The SQRT element has no attributes.

This allows you to specify arbitary roots of an expression. The radix comes first, and is separated from the radicand by the <OF> tag. For example the cube root of 1 + x is expressed as:

<ROOT>3<OF>1 + x</ROOT>

and possibly rendered as:

-------- 3/ 1 + x v

The ROOT element has no attributes.