# How to write equations in LeMill

You can use TeX/LaTeX notation to write mathematical symbols and formulas in LeMill. TeX/LaTeX is a typesetting language for describing formulas in unambiguous way: it might look complicated, but once you understand basics, it is easy to expand to anything mathematical you want to write. TeX is the name of the original math component and LaTeX is the expanded document generation language around TeX. For now on this lesson will call them both LaTeX formulas. (For more information check Wikipedia's articles: TeX / LaTeX)

LaTeX formulas are inserted with this button in toolbar:

The button opens a sheet for writing and previewing the formula. Use the text area to write the formula and use Preview-button to check that the formula returns the correct graph.

The formula is inserted to the current cursor position, either within text like this , or as a separate paragraph:

When you are editing surrounding text, the formula appears in green like this:

You can edit these green formulas like any other text, but click the formula button to open the preview window to check the changes. When you save the chapter, or start editing another chapter these green formulas are replaced with typeset graphics.

You can also start writing LaTeX-formula straight into the editor. If you write, for example \sqrt{\gamma+t} and then select the written text and click the formula button, the selected text is treated as a LaTeX formula from now on: .

## Additional information

http://amath.colorado.edu/documentation/LaTeX/Symbols.pdf -- a cheat sheet of latex symbols and notation. Very useful.

http://www.andy-roberts.net/misc/latex/latextutorial9.html -- a short one page introduction to most often used, but problematic graphical notations: divisions, square roots, etc.

http://amath.colorado.edu/documentation/LaTeX/tutorial/ -- one LaTeX tutorial. Concentrate on sections about maths, as there are other 'environments' that we do not use here.

http://www.ctan.org/ -- headquarters of everything about TeX or LaTeX

http://en.wikipedia.org/wiki/TeX -- Wikipedia links for general information

http://en.wikipedia.org/wiki/LaTeX

## Technical details

The LaTeX / TeX in LeMill uses API provided by Google Chart Tools, http://code.google.com/apis/chart/ and the appearance of the graphs and supported libraries may change as the service changes. If the service stops working, we will find another solution.