Granted, I'm old school. But with a Ph.D. in EE, I've copied a boatload of equations from boards, onto boards, into papers, ad nauseum. I've tried every equation editor out there (this might be a slight exaggeration) and I have to agree that TeX is the best solution. TeX takes some learning, and that's by no means a trivial effort. The most powerful tools we have (like, say, language) take effort to master but the payoff is grand. I've found that when writing papers, and especially when I was writing my dissertation, that equation entry using TeX was almost as fast as I could write with pen and paper and in some cases a bit faster thanks to macros.
The real issue for the original poster, however, is taking notes in class. I have to agree with other replies here: use a notebook and a pen (or pencil, whichever suits you) and scribble your notes. Then transcribe later. Effectively, you will do this later anyway in the process of reviewing your notes and, hopefully, learning from them.
Finally, for my money, take the absolute minimum notes you can get away with. Taking notes during class splits your attention between writing and listening to the lecture. Depending on the instructor, that can get you behind the curve very quickly. I have always found that trying to stay a chapter ahead in the text, which I can do at my own pace and in my own time, was the best way to learn from a knowledgeable teacher. That way you can just listen, follow along, reinforce what you've been working on at your own pace, and when the occasional gem of wisdom comes along (or one of your misconceptions is corrected) you can scribble a few words that will jog your memory later.
But that's just me. YMMV.
Good luck in your studies!