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.

One of Professor Li's greatest strengths is his confidence in mathematics. He is rarely confused about his own work when showing examples, which grants a lot of clarity, even when his speech may be hard to understand at times. He goes quite fast during lectures, but this does benefit the pacing of the class, which is quite even and manageable. My personal favorite aspect of his class is the fair grading scheme and exams. He never does anything that is designed to make you fail or lower your grade. In other words, if you study the material and don't fall behind, Professor Li's class will be as wonderful as any.

I would suggest taking professor Li's class:
Class notes are quite clear and organized. He had all the materials prepared in draft paper that would be presented in his notes with oral explanations in the lectures.
Homework questions are carefully selected. You can review after class.
Professor was always willing to answer questions.
Many students complained that the exams were too hard and they were too different from quiz. It was true. However, you can find all the question types in previous homework. If you really want to have a solid foundation in calculus, the exams will motivates you to work hard and understand key points.

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)

Although this class was challenging and took a lot of time and effort in my opinion, Professor Li did his best to help students understand the difficult concepts. As a new professor, I think he improved greatly throughout the quarter and got better at helping students. I would highly recommend going to his office hours. Although he does not usually give the final answers to homework problems, he will start them for you which is helpful. Even if you cannot attend office hours, he usually would be willing to stay after lectures and help students with homework problems or answer questions. Overall, going to him for help was the best for me since I did not have a good TA.
The homework for this class was assigned weekly every Monday and due on Sunday. Although there were not that many problems, many of them were challenging resulting in the homework taking a good amount of time. I definitely would recommend working on the sections of homework throughout the week and not waiting until Sunday to do the whole assignment. I usually would complete the problems for the most part during the week so I could ask questions during office hours on Friday. This helped me get 100 on all the homework assignments (although he does end up dropping your lowest homework score).
The quizzes were fairly easy. They typically consisted of 2-3 problems and were given in the last 15 minutes of discussion. He also dropped the lowest quiz score at the end of the quarter.
I found the exams in this class to be challenging. However, they did get easier and I think this had to do with the professor wanting to make the second midterm and final not as challenging as the first midterm. Li also offers 2 grading schemes in this class. Scheme 1 included: Homework: 15%, Quizzes: 10%, Midterm 1: 20%, Midterm 2: 20%, and Final: 35%. Scheme 2 included: Homework: 15%, Quizzes: 10%, Best midterm: 30%, and Final: 45%. At the end of the quarter, the professor goes in and calculates which scheme works in your favor. Having the second scheme as an option helped me out a lot since I did not do well on the first midterm.
Overall, although this class was challenging for someone who is not naturally good at calculus, I would say that Li was a good professor who wanted to help students.

Although Math 31B will always be a difficult class, I felt that Professor Li wanted his students to succeed, especially if they put in the effort. He is very helpful and will always try his best to answer a student's question. I would recommend attending his office hours, since I found that this helped answer any questions that I had on the homework/tests. For this class, there were 10 homework assignments, 3 quizzes, 2 midterms, and 1 final. I found the homework and quizzes a good way to boost your grade, while the midterms were the most difficult. But, he made a good portion of the final very similar to the practice final, which made the final a lot easier than both of the midterms. What helped my grade the most was having one of my midterms dropped so the final was weighted more heavily and I believe this was beneficial for many other students in the class. Overall, Professor Li was great and I definitely recommend him as a math professor.

ONE BIG PROBLEM: Lingfeng went to USC!!! Jokes aside, the class is decently easy and straightforward, and I felt like I pretty much mastered the concepts before the final. I was able to do this despite skipping most of this class. Difficulty ramps up significantly weeks 7-10 and into the final. Also, watch out for TRUE/FALSE questions on the tests, specifically the final, as they are worth way to much. I think I got pretty much every FRQ right on the final but 4 missed MC put my final exam grade down 20%. Other than that a fairly good course.

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.