1. differential
2. Linear Algebra
3. Probability
http://www.dartmouth.edu/~chance/teaching_aids/books_articles/probability_book/book.html
Good Source
+ http://pages.cs.wisc.edu/~andrzeje/lmml.html
+ http://www.cs.iastate.edu/~cs573x/studyguide.html
+ http://www.cs.cmu.edu/~tom/mlbook-chapter-slides.html
+ http://nowak.ece.wisc.edu/SLT09.html