The teaching style of Professor Li is very fast-paced as is the nature of the course. To me, I would need to supplement the lectures with the textbook and other resources to fully understand how to do the homework problems. This made some problems in the homework quite frustrating to do. I feel like it would be better if the professor went over more example problems or at least similar problems to what we see in the homework. However, if you do need help with the homework, the professor sticks around after class and talks through some of the concepts that students may find challenging which is certainly a nice thing to do. The professor also doesn't record any of the lectures or post notes to Canvas (he only airdrops them) which is a little inconvenient especially when you have an unlucky seat for the week and someone in the first row blocks the board with their head. Overall, the clarity of the lectures could benefit from more examples and fewer proofs but Fall 2023 is also the very first time this professor is teaching this course so it can only improve from here.

I love Linfeng Li. He’s a super cool and funny guy. Only problems with lecture are his accent can be a bit rough to understand and he tends to copy the textbook for the most part (though he’ll try to answer any questions). The weekly homework’s tend to be pretty short, and the quizzes are extremely easy (there are three during discussion weeks 3 6 and 9). The midterms were rough for me as I made a small mistake on each one that really messed up my score. He was accommodating and gave me a few points back after I explained myself but I ended up dropping that one anyways(he can drop your lowest midterm and increase the weight of the final). The final was extremely fair and very similar to resources he provided in the weeks leading up to it. Everyone I know who prepared well did well on the final, so don’t be disheartened if the midterms are a bit rough. Live Love Lifeng

Math 31B is hard no matter who you take it with. Professor Li was a really funny guy, but he can be kind of hard to understand. When you ask a question in class he will pretty much never understand what you are trying to ask but its ok. My TA was even harder to understand and made me even more confused so I stopped going except for the quizzes (which were super easy). The midterms were hard and required a lot of creative thinking to solve the problems. This class was brutal and I spent so long studying for each exam and for the most part, it paid off once you figured out how he tested. He moves very fast so make sure you pay attention the entire time or else you're going to be very confused. He is really responsive to his emails as well even responding to me at 9pm the night before the final which was really nice.

Trying to write a review from this class, but it was so mentally taxing that I think that my brain has responded by blocking out every memory of this class. TLDR: Homework okay, grading system wack, exams AWFUL, definitely a lot of pros and cons to this class that I will lay out.

I'll try to explain: to preface, I had never taken Calc 2 in high school, and I am now wishing I did. Throughout every lecture, Professor Li mostly just went through random questions, and scarcely expanded on the definitions of terms. It felt like we were mostly left in the dark unless you self studied through the textbook or Professor Leonard/OCT on YouTube. Many other students and I felt confident in the material until the first midterm. There were 5 questions that did not, in one bit, match the difficulty of homework or even in class examples; it was practically impossible. The final average was in the 60s. While the second midterm and final were a bit better, there were still many incredibly difficult problems that did not cover what we learned from class.

That being said, the class is definitely still doable, especially if you have already taken it in the past (many of my friends who have taken an equivalent program felt a lot more okay content-wise). Professor Li didn't usually answer questions during class and it was hard to reach him during office hours because so many people had questions. When you did email and ask questions during class he responded in a very timely matter though, and I am very grateful to him for curving our final grades HELLA and being helpful in his email responses. Overall, I would recommend another section if possible unless you already have a grasp on the content of this subject.

Professor Li's first quarter teaching at UCLA was a rollercoaster. None of his lectures or notes were posted, so be sure to make a friend or two.

He gave no practice materials for his midterms but made up for that by offering a practice final. Some homework problems were more difficult than any examples given in lecture, but that can be supplemented by attending office hours. The quizzes were very straightforward and easy points to gain, in my opinion. My TA, Griffin, was great -- could not recommend taking his section more. Professor Li cares about his students' success, as he stayed after every lecture answering questions that were asked by a gaggle of students surrounding him, but he did not curve the class. It was a frustrating end to my quarter, as I was right at the precipice of an A-.

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.

So, I have some pretty mixed feelings about the infamous new Professor Li. First of all, he is an amazing person, it is his first year teaching (which was very obvious throughout the quarter) and he had a few major flaws. First of all, he seems kind of unprepared when it came to his lectures as he would confuse himself while providing examples, wouldn't go into detail and had some troubles with the mic LOL. His hw was somewhat manageable with about 20 problems to do every week, but I found myself not knowing how to solve half of them with the lectures alone. He also does not give out lecture notes and would sometimes just airdrop them at the end of class which was a mess.. but he would provide less during test weeks. His quizzes are so easy and provides unrealistic expectations as his midterms are way way harder than the homework and the quizzes x2. He gives you some very broad practice problems and tells you they are harder than the midterms but they will usually be unrelated to your midterms and not prepare you enough so study more. He is pretty nice tho like he will take the time to answer emails, meet to tutor and holds office hours. He also allows you to drop a midterm but it does mean your final will be weighted 10% more. One thing that upset me is that he did almost guaranteed a curve at the end of the quarter as his midterm average never cracked a B-, but he ended up ghosting everyone, gave no curve and submitted final grades without an announcement randomly at like 2am and told ppl to do better in the future when a lot of ppl were depending on this curve. He is a nice guy but his ability to communicate with his students is kind of wonky and overall you will find yourself studying and learning concepts on your own but if you really work hard and put a good amount of time into studying outside of lectures you will be okay. (hopefully)

This class is a weeder and the work reflects it. There are 2 midterms, and both are pretty hard if yo do not have conceptual understanding. The professor is good, he teaches concepts well but moves pretty quickly so you risk missing out if you don't pay attention, and office hours are recommended to understand concepts better! There are 3 quizzes in discussion sections.

I love Lifeng Li. He is really sweet and genuinely cares about his students. In his lectures, it was obvious that this was his first year teaching. His lectures became more clear as the quarter went on. He is very intelligent and his office hours were very helpful. His tests were a bit tricky. He basically combines multiple topics into a single question, and you have to figure it out on your own. I had taken Calc BC in high school, so this wasn’t a problem for me. The class is not curved, but the averages on all tests were in the 80’s. The homework is due every Sunday and can get lengthy, but it’s still doable in one day. The grading was based on homework, quizzes(2 questions, really easy), two midterms, and the final. The grading scheme is really fair. Overall, I recommend this class, especially if you are a math person.

Professor Li is not easy, but he has reasonable expectations that he makes fairly clear. The lectures are not recorded, but he teaches directly from the book—I didn't attend many lectures and honestly think you're better off reading the textbook than attending Li's chaotic lectures. There are three quizzes during discussion sections: they are all basic and the lowest quiz score is dropped. The midterms and final are not easy by any means, with averages around 60% to 70% for all the tests, although there are two grading schemes (one with both midterms, one with only the best midterm). I never attended OH, but I heard Li is very receptive to students seeking help. At the end of the quarter, he adjusted the grade bounds down by almost 5%, so high grades are not impossible at all.