Koffi is an extremely nice and affable professor, but that doesn't make up for how difficult it is to learn the material in his class. He goes over material extremely fast and skips steps all over the place, which makes understanding him through the live lectures almost impossible(I had to watch youtube videos in order to supplement the topics). The worst part isn't his bad handwriting or his really fast pace (even for a summer class) it's the raw amount of hw he assigns. He assigns 15-30 problems per lecture and they tend to be long, complicated, and harder than the tests problems. DO NOT wait to do these if you take him as he grades them for accuracy and they count for 20% of your grade.
Overall I wish he was better at teaching because he is very excited for people to learn and did give a generous extra credit opportunity in the form of a real-world math project, however, this class can be much easier if taken with other professors.

The professor was incredibly kind all throughout the summer session. The class was relatively easy comparing to my other math classes but I'm guessing this is because difeq is a lot more of a problem solving type of math rather than like proofs and stuff. I liked the professors style of giving a lot of homework because it did make me learn a lot more but be warned it's quite a bit. He didn't set a deadline for any of the homework and just made it so that you can turn it in at the end of the quarter. Well, I procrastinated and the last few days were just misery. He makes you do upwards of 15 problems a day for every class day. The midterms and finals weren't bad however (very expectable) and he even offered an extra credit project. He really wants you to participate!

I was nervous for Math 33b before the course begins given the poor rate the Professor has on Bruinwalk, but Professor Koffi was such an engaging and very knowledgeable professor. He organized many extra review sessions (especially before midterm and final exams) where he went over many of the exams' study guide problems. He hosted many extra evening office hours. His homework assignment load was overwelming though, but he was very flexible with the submission deadlines which i pretty much appreaciated. I learned a lot from his course. Great professor!