This is a collection of formulas, definitions, and other math stuff I have had to look up, find out, struggle with, and decided to write down for the future refence. The pdf version is on gh-pages.
Feel free to use and copy the formulas here. But be careful -- there is probably a number of errors and misunderstandings!
The cheatsheet started around 1999 when I studied economics at Tartu University and wrote a sheet (yes, a single sheet ;-) of formulas to help my coursemates with math. There are still many pieces of text from that time, in particlar those related to limits and Taylor's approximation. The pages filled with Tobit and duration models' Hessians are leftovers from my Master and PhD thesis. I wrote it in Estonian back then, and I don't intend to translate it just for translation's sake. Only if I am rewriting an old piece of text I'll do it in English.
Have fun!