> Because often the instructor or professor may ad lib based on a question from a student. It may result in a really good answer that probably won't be in the o

> Because often the instructor or professor may ad lib based on a question from a student. It may result in a really good answer that probably won't be in the official lecture notes. Exactly, that's why I said everyone should get a copy of the official notes beforehand and write down their own notes on them. It's much more efficient than slavishly copying everything you hear, making it harder to pay attention.