[EricH]

With respect to taking notes: If you have a laptop that you take notes on, ditch it, IMO. I get one of those 80-page lab-type notebooks and take notes in it--I can get about a semester of notes for 3-4 classes into one of those, and they're cheap. Taking notes on the laptop, I was more inclined to play computer games or mess around a bit.

Why there are different formulas for the same thing is a bit tougher, but it's easier to graph an equation in some forms than in others. And if you ever take Differential Equations, there are probably about 3-4 ways to solve any given differential equation. And every last one of them has a different procedure...