I did not enjoy this class because I suck at calculus, but Li was a good professor. He seemed to be concerned with our success and was open to our feedback as a relatively new professor. Lectures and discussion didn't require attendance. There were 2 midterms, a final, and 3 quizzes (in discussion section). Discussion sections usually just involved practice problems. The quizzes were pretty easy (I had a good TA who helped us prepare for every quiz) and the exams were tough, but I think if you study a lot you can do well (I'd recommend doing just a lot of practice problems). For all of the exams, Li gave us a few formulas, but you weren't allowed to have a cheat sheet, so memorizing all of the formulas and theorems is tough. Lectures weren't posted anywhere, but you could get that week's notes from him every Friday after class. Overall, not a horrible class, and Li is a decent and fair professor.

Professor Li is an upper professor when it comes to teaching calculus. If you took BC in high school this class should be a cakewalk. Professor Li takes notes with you as he usually writes down a theorem, then does one or two practice examples before moving onto the next concept. He shows you how to break a problem down and how to approach a problem which is super nice. He is a young guy who is super helpful when it comes to needing more understanding and is also pretty fun. The class is broken down by homework, quizzes, 2 midterms, and a final. The homework is not very difficult and doesn't take super long, however, I wouldn't wait until each Sunday to complete them. If you verify your answers online, there is no reason you shouldn't get 100%. There are 3 quizzes which are 3 problems each, with examples close to the examples he gives in lecture and in homework. If you pay attention in class and work through some homework problems before the quiz then again there is no reason you shouldn't get 100%. Onto the midterms, they are definitely a bit more challenging but the key to success is to do as many practice problems as possible. Honestly if you do 20 practice problems before the midterm, with harder difficulty, the midterms should be completely straightforward. The final is pretty challenging, but again if you lock in and do practice problems there is no reason you shouldn't get at least a B on the final. He sets the thresholds for A, B, C, D down at the end of the class to adjust for test scores which is helpful for the GPA as well. Overall, Li has mixed reviews and I believe it is because of his tests, however, if you pay attention in lecture and don't skip them, you will learn the material inside and out and succeed in this class.

Easy class mid professor.

My experience with this class is that if you do the homework problems yourself and truly understand each one, you will be able to ace his exams. The midterms are not too bad, you just really need to be able to understand patterns and applying what you learn. The final was more like a huge unit test which did not focus on anything which was before midterm 2. There is a lot of partial credit given so even if you got the wrong answer on a problem, the amount of work you showed adds up and helps you gain some points. Overall, I think the class is extremely doable as long as you are willing to put in the effort.

Overall I liked 31B taught by Professor Li but I wouldn't say this is an easy class.
Good things about this class:
1. The professor is very helpful, he replies to your emails in a timely manner and is often willing to stay after class to answer your questions.
2. Workload is manageable, he gives less work during Thanksgiving break/midterm week.
3. Professor Li is genuinely a nice and chill person.
But there were things that went not so well:
1. Classes are not recorded or broadcasted.
2. Midterms were hard but the Professor was generous with partial credit.
3. The professor's teaching could've been clearer.

I thought my high school BC teacher was bad but this guy is even worse. He often does 20% of a problem then makes you do the rest on your own time. Professor Li also doesn't post his notes online or record his lectures, instead airdropping them at the end of each week so you better come to every lecture. His quizzes are very easy but the midterms he has given us have had some weird problems he hasn't really taught us how to solve (especially midterm 2). Professor Li occasionally earrapes the class as he isn't that good with the mic. I'm somewhat getting by in his class, but if you're coming from Calc AB or Math 31A/Calc I, good luck.