Create tables made easy

This tools provides a great help when creating LaTeX tables from html, xls, etc formats and vice-versa. 

https://www.tablesgenerator.com/latex_tables

Convert latex equation to png

A nice web resource to convert latex equation to .png figures is latex2png

How to write nice equations in LaTeX beamer

The equations in the default beamer presentation slides are rather unattractive.
In my opinion this is merely because of the fonts used for equations.

You can change it by changing the font-theme for equations.

 \usefonttheme[onlymath]{serif}

 This will result equations like in the articles in your beamer presentation.

For further hints check out this post.

Latex symbol converter

This is a resource where you can convert any text (utf8) to latex symbol notation.

http://w2.syronex.com/jmr/latex-symbols-converter

Maple output to LaTeX

Maple can produce latex source using the ... wait for it ... latex( . ) command :-D

latex(expr, options) latex(expr, filename, options) See here for more details. Works on Windows and Linux as well, no experience with OSX (yet).

This is hardcore!

web.mit.edu/rsi/www/pdfs/advmath.pdf

Hardcore latex math, thanks for all contributors

diff LaTeX documents

This is a great stuff to diff latex docs:

http://www.ctan.org/tex-archive/support/latexdiff

you might also be able to install it for your ubuntu for instance using

$ sudo aptitude install latexdiff

Usage:

$ latexdiff old.tex new.tex > diff.tex

This will create a new file called diff.tex, which is a valid LaTeX document countaining the difference between the two, if old.tex and new.tex were also valid LaTeX docs, and you can proceed diff.tex as you normally would creating eps, pdf, html, etc ...

If you don't want to or can't install the tool, it's available online here:
http://3142.nl/latex-diff/

If you are using version control like svn or cvs, you might consider using the latexdiff-vc command, that actually makes the diff from the version in the version control. More resources about this you can find at the links below:

http://kwtrnka.wordpress.com/2010/11/28/latexdiff-version-control/  

http://www.jwe.cc/2012/02/workflow-with-subversion-and-latex/ 

For example I use

 $ latexdiff-vc --svn -r <oldversion> --pdf <mylatex.tex>

in order to generate pdf diff in one step

This is cool :) You don't know how ti write a LaTeX symbol, detextify it!

If you are looking for a symbol, but don't know how to LaTeX write it, you may use detexify:

http://detexify.kirelabs.org/classify.html

How to write new line in LaTeX

Many LaTeX user (as myself in the past) think that the form of new line is to write

\\

Well, it works, bit it is actually not new line, but starting a new paragraph
The correct notation for new line (but not new paragraph) is

\\*

A more detailed description with many other possibilities to write new line new paragraph, new page is available at
http://www.personal.ceu.hu/tex/breaking.htm#newline

Write comments in LaTeX

Normally comment is written in LaTeX with '%'. This rather suggested for short, one line comments, because the effect is only valid till the end of the line. If you would like to comment an entire block, it's more convenient to use the verbatim package as

\usepackage{verbatim}
 ...

\begin{comment}
  ...
  commented text
  ...
\end{comment}

How to leave open parenthesis in equations

If you use \left( and \right) the syntax checker will not allow you not to close (or not to open) the parenthesis. To get your LaTeX code correct you have to use \left. or \right. to have it closed.

This is useful for instance when you want to add new lines with parenthesis open or write cases like 

$\left\{
   \begin{array}{l c l}
      x &\rightarrow& y \\
      z &\rightarrow& w
    \end{array}
\right.$

How to use multiple .bib files

Bibtex files are countaining references. In some cases we would like to use multiple .bib files, these we can simple enumerate in the  \bibliography command
as

\bibliography{file1,file2}

where file1.bib and file2.bib contain the references

Collaborative editing

My first guess for collaborative editing was googledocs with latexlab as described here.
But this in my opinion has serious privacy issues.

Some other ideas are text tracking systems, like svn or git as back-end. A collection of possible methods can be found here.

However this topic is still unresolved.

Update: there are two main alternatives for online collaborative editing:

• Sharelatex
•  Overleaf

How to write math equations inside your blog

See here for instructions