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So let's see some math in \LaTeX: $\sqrt{a^2+b^2}$, $\lim_{x\to\infty}\frac{2x+1}{3x+5}$,
$\alpha = \psi\circ\beta\circ\psi^{-1}$.  And
$$
\lim_{x\to\infty}\frac{2x+1}{3x+5} \qquad\qquad \sum_{i=1}^\infty \frac1{n^2} 
     \qquad\qquad \{r\in \mathcal{R} : r^2<0\} = \emptyset
$$
As you can see, the command words are usually easy to figure out.  Underbar means 
the next symbol (or group of symbols, if they are bound together in braces) is 
made a subscript, and caret means superscript.  Some command words, like the one 
for limit, just put the same word in normal (Roman) type.  One tricky thing is the 
symbol I've used here for the real numbers, a capital R is ``mathematical 
calligraphy'' type.  Notice the differences between $\phi$, $\varphi$ and $\emptyset$;
and between $\epsilon$, $\varepsilon$ and $\in$.
 
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