# LaTeX Equation Environments

As we all know, there are many equation environments to choose, including

`equation`

`multline`

`align`

`eqnarray`

`IEEEeqnarray`

I prefer

`$$`

for inline equation`equation`

for single-line equation`IEEEeqnarray`

for multi-line equation and equations

To use IEEEeqnarray, you should install IEEEtran, which can be downloaded at http://mirror.ctan.org/macros/latex/contrib/IEEEtran.zip

On Arch Linux, using texlive, I just use texconfig -> CONF to find the path of TEXMFLOCAL, and make a folder TEXMFLOCAL/tex/latex/IEEE and copy all the files in that folder. Finally, run texhash.

You should add this line in the preamble of your LaTeX file

```
\usepackage[retainorgcmds]{IEEEtrantools}
```

To add an IEEEeqnarray, use

```
\begin{IEEEeqnarray}{rCl}
\end{IEEEeqnarray}
```