There are three environments that put LaTeX in math mode:
math
displaymath
equation
The math
environment can be used in both paragraph and LR mode,
but the displaymath
and equation
environments can be used
only in paragraph mode. The math
and displaymath
environments are used so often that they have the following short forms:
\(...\) instead of \begin{math}...\end{math} \[...\] instead of \begin{displaymath}...\end{displaymath}
In fact, the math
environment is so common that it has an even
shorter form:
$ ... $ instead of \(...\)
The \boldmath
command changes math letters and symbols to be in
a bold font. It is used outside of math mode. Conversely, the
\unboldmath
command changes math glyphs to be in a normal font;
it too is used outside of math mode.
The \displaystyle
declaration forces the size and style of the
formula to be that of displaymath
, e.g., with limits above and
below summations. For example
$\displaystyle \sum_{n=0}^\infty x_n $