Nice guy but doesn't explain anything well in lectures. The class is graded by practically nothing so even a few points off on the test is a hard hitter for your grade. Some things on questions weren't taught at all as well.

I gave up on this class. Not only did he overcomplicate formulas, but he switched to solely online lectures not even halfway through the quarter. If the lecture is online, then so should the rest of the course (exams, etc), but they weren't. Final is like 40% of grade along with 2 midterms, homework, and labs.

Very nice human, not a great lecturer. Only take his class if you are good at teaching yourself, because a lot of his "teaching" was just him mumbling to himself and expecting us to understand. Graded mostly on the final and your maximum score of the two midterms. Would not totally recommend, but this class is alright as long as you talk to your TA

This guy, as sweet as he is, does not know how to teach. He teaches as if we are already supposed to know the information presented which makes lectures hard to understand. I had to teach myself the whole material and the TA's are honestly carrying this course. I would not recommend.

Professor Duan is very sweet, however, does not know how to teach. His lectures are a pain to get through as he doesn't do a good job at explaining the material. The TA's are carrying the class as they basically have to re-teach everything in section. Love the guy, but I would never take a class with him ever again.