15. Typesetting Mathematics

A big advantage of LaTeX is that it can be used to prepare documents containing complex mathematical formulae. In this chapter, we examine how to typeset mathematics with LaTeX.

15.1. The three environments - math, displaymath and equation

Let us typeset an equation in three different ways. Here is the LaTeX document:

\documentclass {article}
\begin{document}


Here is a formula: $E = mc^{2}$

Same formula, but this is typeset differently: \[ E = mc^{2} \]

Same formula again, different typesetting:
 \begin{equation}
 E = mc^{2}
 \end{equation}

Repeat:
 \begin{equation}
  E = mc^{2}
 \end{equation}

\end{document}

This is the output which LaTeX generates:

When an equation is written between two “$” (dollar) signs, it is said to be in math mode. In the above document:

$E = mc^{2}$

is in math mode. The equation is displayed in the same line (it is called an in-text formula). When the same equation is written between a “\[” and “\]”, it is said to be in displaymath mode; it is displayed on a line of its own.

When the equation is written between a “\begin{equation}” and “\end{equation}”, LaTeX gives it an equation number - the first equation is given the number 1 and subsequent equations are numbered 2, 3 and so on.

Now, how do you really write an equation? Mathematical equations are full of symbols which we rarely use when writing normal text - LaTeX has a syntax of its own for representing such symbols and symbol combinations. The equation:

itself is a good example. LaTeX displays the number 2 as a “superscript” when the “^” operator is used.

15.2. A few examples

Given below are a few samples of the kind of mathematical expressions you can create using LaTeX (the expressions have to be in one of math, displaymath or equation modes - that is omitted in the examples).

LaTex Command:

x_{i}

result:

LaTeX command:

p = \frac{a+b}{a-b}

result:

LaTeX command:

\sqrt{a+b}

result:

LaTeX command:

\sqrt[n]{2}

result:

LaTeX command:

\alpha \beta \pi

result:

LaTeX command:

\leq

result:

LaTeX command:

\not\leq

result:

LaTeX command:

\sum_{i=1}^{n} x_{i} = \int_{0}^{1} f

result:

LaTeX command:

\lim_{n \rightarrow \infty} x = 0

result:

LaTeX command:

\overline{a+b}

result:

LaTeX command:

\underline{a+b}

result:

LaTeX command:

\overbrace{a+b+c+d}

result: