### Preface

Goal: Write a Math Formula with LaTex.

I wish someone introduce me to LaTex, while I was studying Engineering Degree. Despite of my regret, I would like to introduce it to you. So that you can use it in daily lives, from just making school paper, or just to communicate your idea in social media.

### Standalone

Now that I meet Data Science, and Functional Programming, I also have a need to write down formula, in a blog using MathJax. And sent Formula via Telegram or Whatsapp using PNG image.

Now here is the issue?
I use LaTeX to create PDF, with output as pages.
The output of the `article`

always give a big page.
I never use it to create standalone small images.
And the output does not fit well with formula.
It is always show one page, even for a small formula.

Luckily the word `standalone`

helped me find the answer while googling.
Now the output is only that little formula.

```
\documentclass{standalone}
\begin{document}
{\Large
$\displaystyle
\lim\limits_{x \to \infty} \exp(-x) = x
$
}
\end{document}
```

Then run the folowing command

```
$ latex equation.tex
$ dvipng equation.dvi
$ feh equation1.png
```

This will show you this below:

Not good? How about some decoration?

```
$ dvipng equation.dvi -D 200
$ convert -border 20x20 -bordercolor white math-051.png math-052.png
$ feh equation2.png
```

This will show you this below:

If you need a cool image, I can show you LaTeX in ViM.

If you wish you can also enable transparent background with `dvipng`

.

`$ dvipng equation.dvi -D 200 -bg transparent`

### Install

You might also need to install extra package, and it depends on your system.

#### Gentoo

```
$ sudo emerge -av texlive-latex
$ sudo emerge -av dvisvgm
$ sudo emerge -av texlive-latexextra
```

#### openSUSE

This will install 2148 packages on openSUSE 15.1

```
$ sudo zypper install texlive-latex-bin-bin
$ sudo zypper install texlive-standalone
```

Or if you need `cases`

:

`$ sudo zypper install texlive-cases`

### Aligning Multiline Equation

After a few trial and error,
I found a way to write down multiple equation with alignment,
in `standalone`

document.

#### Indentation Issue

```
\documentclass[
preview
]{standalone}
\usepackage{amsmath}
\begin{document}
\begin{equation*}
\begin{split}
\nonumber
f(x) &= \frac{5x + 6}{4}\\
&= \frac{5x + 6}{4}\\
\end{split}
\end{equation*}
\end{document}
```

As you can see, the figure has undesirable left margin.

#### How to Solve ?

Just set indentation to zero.

```
\usepackage[fleqn]{amsmath}
\setlength{\mathindent}{0cm}
```

#### Example

```
\documentclass[
preview
]{standalone}
\usepackage[fleqn]{amsmath}
\setlength{\mathindent}{0cm}
\usepackage{amssymb}
\begin{document}
\begin{equation*}
\begin{split}
\nonumber
&& f(x) = \frac{2x}{4x - 7},
x \ne \frac{7}{4}\\
\Rightarrow && y &= \frac{2x}{4x - 7}\\
\Rightarrow && 4xy - 7y &= 2x\\
\Rightarrow && 4xy - 2x &= 7y\\
\Rightarrow && x(4y - 2) &= 7y\\
\Rightarrow && x &= \frac{7y}{4y - 2}\\
\therefore
&& f(x)^{-1} = \frac{7x}{4x - 2},
x \ne \frac{1}{2}\\
\end{split}
\end{equation*}
\end{document}
```

### I am Normie

But hey, I’m not a coder ? How do I start ?

#### Tea Inside

For non-savvy person,
the easiest way to accomplish this is to use TeaLaTeX compiler,
created by a talented young man named **Ammar Faizi**.

Just try a few LaTex, and this site will compile the result for you.

#### Source Code

How about source code? I do not have linux ricing to show eye candy code.

Well, you can utilize carbon.now.sh. Paste your code and voila.

### Conclusion

I know that his article is short. It is intended to to be a very basic start to LaTeX.

That is all. This is my first article in January 2020. A short article that might has big impact. Because I am going to need a lot of LaTeX, later on.

LaTeX is easy. Let’s have some fun with it.

What do you think ?