
This document has a little bit of text, and a little bit
of equations.

First, we can put really simple mathematical expressions
like $\pi$ or $\sin(x)$ into the text by surrounding
them with dollar signs.  We can put simple equations
into the text in the same way, like this: $y = 2x$.

But if we want to display a complicated mathematical expression,
we really ought to place it on a line all by itself.
Surround the equation with pairs of dollar signs, like this:

$$
y = A \sin(\omega t) + B \cos(\omega t)
$$



\bye

