## Class files

The feature that makes L a T e X the right edition tool for scientific documents is the ability to render complex mathematical expressions. This article explains the basic commands to display equations.

# Introduction

Basic equations in L a T e X can be easily "programmed", for example:

The well known Pythagorean theorem $$x^2 + y^2 = z^2$$ was
proved to be invalid for other exponents.
Meaning the next equation has no integer solutions:

$x^n + y^n = z^n$

As you see, the way the equations are displayed depends on the delimiter, in this case    and    .

# Mathematical modes

L a T e X allows two writing modes for mathematical expressions: the inline mode and the display mode. The first one is used to write formulas that are part of a text. The second one is used to write expressions that are not part of a text or paragraph, and are therefore put on separate lines.

Let's see an example of the inline mode:

In physics, the mass-energy equivalence is stated
by the equation $E=mc^2$, discovered in 1905 by Albert Einstein.

To put your equations in inline mode use one of these delimiters:    ,    or  \begin{math} \end{math}  . They all work and the choice is a matter of taste.

The displayed mode has two versions: numbered and unnumbered.

The mass-energy equivalence is described by the famous equation

$$E=mc^2$$

discovered in 1905 by Albert Einstein.
In natural units ($c$ = 1), the formula expresses the identity

\begin{equation}
E=m
\end{equation}

To print your equations in dosplay mode use one of these delimiters:    ,    ,  \begin{displaymath} \end{displaymath}  or  \begin{equation} \end{equation} 

Important Note:  equation*  environment is provided by an external package, consult the amsmath article .

# Reference guide

Below is a table with some common maths symbols. For a more complete list see the List of Greek letters and math symbols :

description code examples
Greek letters  \alpha \beta \gamma \rho \sigma \delta \epsilon $\alpha \ \beta \ \gamma \ \rho \ \sigma \ \delta \ \epsilon$
Binary operators  \times \otimes \oplus \cup \cap $\times \ \otimes \ \oplus \ \cup \ \cap$
Relation operators  < > \subset \supset \subseteq \supseteq $< \ > \subset \ \supset \ \subseteq \ \supseteq$
Others  \int \oint \sum \prod $\int \ \oint \ \sum \ \prod$

Different classes of mathematical symbols are characterized by different formatting (for example, variables are itzlized, but operators are not) and different spacing .