The theorem does not really have a name. I wanted to give it a name so it will be easy to refer to it in the future (we will be using it *a lot* in Units 12 , 13, and 14). I made up the name Big Theorem for two reasons: 1) it tells us how "big" different sequences are with respect to each other (so it is a theorem about "big"). and 2) it is perhaps the most useful result you will learn about sequences (so it is a big theorem). By the way, most calculus courses do not include this theorem, which I find disappointing.
