LaTeX is a document preparation programming language.
Great resource for how to use LaTeX - http://en.wikibooks.org/wiki/LaTeX
You can install latex on all operating systems: If you’re running Linux, installing LaTeX is as easy as using a package manager. For Windows you may want to try installing the Miktex distribution. For Macs, the TeXShop interface is available.
Easy to use, online, collaborative LaTeX editor. Highly recommend due to the fact it is easy to share with collaborators/supervisors etc.
Mathematics Online Editor (or Math Editor) . Developed to help people to quickly write any mathematics formula/equation. People don't need to know about LATEX, but still have a powerful and rich Mathematics symbols/layouts/features so they can share with others.
Complex and powerful tool to create vector graphic elements in LATEX.
Forgotten what the latex command is for a symbol in LaTeX? Use: