Hi, I have completed both my bachelors and masters in the computer science field. The thing is, to go further …in maybe research oriented stuff. I would need to prove theorems and algorithms which for now..I do not think I am good at. I have to start from the basic, and I remember doing some mathematical subjects back in undergraduate days, but even then I did not do well in subjects like..design analysis & algorithm or discrete structures. .and I think I have to learn calculus for that, where do I start, any beginner calculus books that I can find on the Net ? And how do people actually prove theorems and algorithms in computer science, what other mathematics subjects that should be suggested to people like me?