Help arrives, drunk.
If anybody needs a review sheet for an introduction to differential equations course, I had to make one recently for awful, terrible reasons beyond my control. You can find the sources to de.tex and de.sty on Pastie, however long they’ll last. At most, until MySpace and 4chan team up to buy out the internet.
And, if you can, avoid Nagle’s Fundamentals of Differential Equations. It focuses all too much on applications before explaining the theory, and it does the latter in a willfully obtruse manner. Given the alternative of hearing it from a teacher again, the matrix exponential function chapter would probably lower your test scores.