Building math structures
Variables and constants are simple. But there are more complex objects, such as binomial coefficients, vectors, and matrices. We shall figure out how to typeset such structures.
Let's begin with simple arrays.
Creating arrays
For arranging math expressions within a surrounding expression, there's the array environment. We use it exactly like a tabular environment. However, it requires math mode, and all of its entries are made using math mode as well.
For example, we can use variable-sized parentheses around an array:
\[
A = \left(
\begin{array}{cc}
a_{11} & a_{12} \\
a_{21} & a_{22}
\end{array}
\right)
\]
This produces a matrix:
Figure 9.33 – A simple array
There are specific commands for matrices.