LaTeX - Math Formula

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.

• latex.teainside.org/

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 ?