This was his first class at UCLA, so he definitely wasn't the greatest lecturer, however, he was clearly very caring for his students and could be quite funny during lectures. His exams were extremely straightforward and I did well up until the final which I hardly studied for and rightfully did terrible on, which dropped my grade from a comfortable A to barely a B. Overall, I only expect Haoren to get better as a lecturer and I would definitely recommend him for this class.

Underrated in my opinion. He goes through material in an efficient and clear manner, and releases homework every lecture (just a few questions). Furthermore, his lectures (at least during fall 2022) were recorded, so you didn't have to attend lectures physically at all. His practice midterms are extremely similar to his actual midterms, so I would recommend doing them.

Overall, I have found this course to be very enjoyable and informative, and Haoren is an excellent lecturer who explains the material very clearly. I especially appreciate that he provides helpful notes that are useful for reviewing, and that he always uploads the lecture recordings on time. Based on my experience, I would highly recommend him for 31B.

However, I did find the final exam to be quite challenging, even though I thought I had prepared well and was hoping for at least an A-. Unfortunately, I ended up with a B+ instead. On the other hand, the midterms were much more straightforward and closely resembled the practice exams, so I found them to be manageable with sufficient preparation. For anyone planning to take this course in the future, I would suggest being aware that the final exam may be more difficult than the midterms, and taking extra time to prepare accordingly.

This is his first lecture ever taught, and I'm surprised by how fast he improved his style of lecturing. His exams weren't the easiest, but if you study hard you will end up with a good grade. Definitely would take another course with him.

Haoren is a kind person and I think it is possible to do well in his class. I took this class my first quarter here and his first quarter at UCLA. I came in having done well in AP calculus AB (I got a 5 on the exam and did really well in the class). The content's logic level was similar to the material from calc AB(and I assume 31a). However Haoren's teaching method was very difficult to understand--I do best when I am plainly told which methods to use for which problems. In each class, Haoren simply started solving different problems while vaguely narrating each step with out explaining why. It felt like he was reading from the textbook. When students asked questions, he would give a quick response and then keep solving without checking to see if his explanation made sense. Sometimes when people asked him why he was doing something, he would say, "this is just what the textbook says". My TA, Zerrin Vural was great. During discussion, she would explain things in a way that made much more sense to me! Also each lecture was very similar to the textbook, so towards the end of the quarter, I started reading the textbook before lecture which helped a lot. The lectures are also recorded and he doesn't keep track of attendance. Haoren's office hours were also really helpful because he would show how to solve confusing problems from the homework and practice midterm--I found these more helpful than the lectures. The class was well organized and I felt that the tests were very similar to the practice tests. I think that I did so poorly, not only because of the teaching style, but also because of a mix of the TA strike, being overloaded by my other STEM classes, having the midterms returned 2 days before the final, and being new to UCLA. Still, I think I would have been able to get higher grades with less effort with a different professor. I would recommend trying to take the class with a professor who has more experience teaching/is better at explaining things. I know a lot of people are struggling in his 31AL class right now as well. If you do take this class, I recommend going to office hours and making sure that you understand everything in the practice midterm.
Also here is how it was graded:
15% Homework-graded on correctness, 2 lowest homework scores dropped
There are 2 midterms and a final
There are 2 Test Grading Schemes--they will chose whichever is higher
A: 20% each midterm, 45% final
B: Highest of the two midterms for 30%, Final 55%

Haoren Xiong is a great professor, while his lectures may be a bit dry, it's more so the content rather than his lecture style. His lecture slides are incredibly detailed, comprehensive, and useful when doing homework. In addition, he spent his virtual office hours helping students with homework problems and basically walked us through the problems step by step. While the final was a step above in difficulty compared to the midterms, he also gave us an overview ahead of time of what the format would be and instructed us on specific topics to focus on when studying. His lack of experience can cause some hiccups when it comes to his overall administration of the class, but he does his best to be as accessible and friendly as possible.

Professor Xiong focuses so much on proofs that he doesn't do application problems which was difficult when it came to homework and exams. He's a super nice guy and new professor so he is pretty accommodating, but the reason I did well in the class is probably more credited to taking Calc BC in high school (it's literally the same class). TA's are also super helpful.

haoren was traumatizing. period. He picks THE HARDEST QUESTIONS from the textbook for each homework and his tests were tough af.

Chill funny guy. Massive advantage to the people who took AP Calc BC, but that's true for any 31B professor. From what I have heard, his class covers easier problems than other 31B professors and his midterm/final exam averages were much higher as well. Overall his teaching style was solid, going over the concept in the start of lecture and then doing a couple problems. Workload is very light, only like 5 or so problems a week, but if you're struggling with the content or didn't take Calc BC doing a few more would def help. His practice midterms helped tremendously for the midterms, and both were very fair. The final was difficult, but still fair. Overall solid, would take again, probably better than your other options.

I personally loved Haoren. For someone who doesn't like math, I learned a lot and was able to make sense of so much more than I thought. The lectures are good and understandable and the recordings are great too (if you dont wanna go to class). Plus, workload is great. He gives a few questions after every lecture and that accumulates to a weekly homework. And, he accommodates for mid term weeks so you have more time to finish the homework. The discussions are pretty helpful IF you decide to go. You solve a worksheet in each discussion (so twice a week) and they make up 5% of your grade. BUT discussion is also NOT COMPULSORY till the time you just submit the worksheet the same night at 11:59pm. I would 100% recommend taking him for this class and I am 100% looking forward to taking his 31b class next quarter too.