Fatou's lemma

Fatou's Lemma is a theorem that lets us figure out what the limit of a sequence of numbers is. A limit is when a number keeps getting closer to a particular value, and it will never reach that value but it will always be close to it. So with Fatou's Lemma, you can take a number sequence where the numbers keep getting closer to a certain number and you can calculate what that number will always be close to.