bohan fang is a nice guy, and he will always try to help if you approach him. also, the class is quite easy because he gives practice midterms that are exactly like the actual midterms, and if you know the practice midterms, midterms, and practice final very well, you'll have no problem on the final exam. that being said, professor fang is one of the worst teachers i've ever had. i say this with no exaggeration or spite, but rather to offer my honest advice: do not attend the lecture, it will certainly hurt your comprehension of the subject. read the book on your own, watch MIT opencourseware lectures, find tutors in the math help room, but whatever you do, DO NOT ATTEND THE LECTURES. you will not be able to understand a word he says, his notes are disorganized, his chalkboard handwriting is dismal, and he provides no narrative whatsoever (not even simple motivations). he also expects you to know certain things that you may or may not know, and if you don't know those things going into the lecture then the steps he takes in examples and proofs will make no sense. what's worse, he doesn't say what he's expecting you to know, or even allude to the blanks you're supposed to be filling in on your own, so if you don't recognize where it is that you're missing a critical step, then the notes will be depressingly confusing. just stay away from the lecture room until exam time, work hard on all the homeworks and practice tests, and you'll do well in the class,.
His lectures are awful (he always looks at the ground, can't understand a word that he's saying) and you will learn nothing from them, but thats okay because this class is easy as fuck. He often repeated questions from practice midterms on exams - like with the same numbers and everything. Do the practice midterms and you will be golden. Weekly problem sets with some dumb problems but what do you expect its a math class. Shoutout to TA Oren who promptly answered my questions via email.
I enjoyed this section because I love calculus, and I thought it was easy because Bohan tends to curve a lot. You don't even have to go to class! Just read the textbook and do practice problems. His accent is hard to understand, and the lecture notes you copy down from the board won't make sense to you later, so going to class is unnecessary. You would be lucky to get in his section, unless you like going to calculus class. I got an A so I was obviously excited about the class considering the amount of effort I put in.
I was incredibly disappointed with this class. Mr. Fang's English is terrible. I was unable to understand him the entire semester. It is hard for me to believe he is an instructor at all, much less at an Ivy League school. I have grown accustomed to the typical math instructor at Columbia, by which I mean the tendency here is to have instructors who can't teach very well. Mr. Fang goes several steps beyond the typical socially uncomfortable professor. He is disengaged and unhelpful. Take this class only if you need no verbal component to classroom instruction, because you will not get it.
I disagree with the previous reviewer in that Calc III is still a bit tricky if you're not amazing at math like so many here are, but I do concede that Fang is probably the easiest Calc III professor at Columbia. He is quiet and does have an accent, but his accent is completely understandable; he also stutters often. He may not show it, but he really does care about his students/teaching. I went to every class, but most didn't bother to show up (which was probably smart). I didn't read the book till before each exam (oops) and Fang basically just writes down everything that was in the book. That's basically every lecture. If you ask a non-stupid question though... don't bother because his answers will mostly be crap/repeat since he doesn't seem to fully understand what is being asked. He's very clear about what will be on the exams and what will not, though he doesn't like people asking about the grading/curves. Also, he'll tell you how difficult the exam will be compared to the practice exams that he posts-- usually they're about the same difficulty. Overall very fair professor, and easy course.
Calculus III is one of the easiest classes at Columbia, and Bohan has got to be one of the easiest professors. My final asked one problem which only required you to know the quadratic formula and that sqrt(-1) is denoted as i. Really. My advice is to go to class 6 times during the semester: the first day so you learn where to drop off the homework, the day before each midterm, the midterms themselves, and the last day. He does a review class before each exam, and will probably point out something you forgot. If you have the ability to focus on the textbook for an hour and 15 minutes, you will get through a lot more than Bohan does in class, and understand it better. He's quiet and has a substantial accent.
If you've taken the class elsewhere, and simply need to take it at Columbia since Columbia doesn't give you the credit from elsewhere, take this class. It'll be easy. You may choose to not go to class. I still went to all lectures. They weren't helpful, but if you can learn the stuff on your own, it doesn't matter. The homework was somewhat annoying, but since they comprise an insignificant portion of the grade, it doesn't really matter if you can't get through the long proof. The exams were easy. Compared the ODE class I took in high school, this was a joke. Sure they got harder, but they were very challenging in a doable way. Again, you'll only find it fun if you're really into math, and have some knowledge of ODE beforehand. He generously gives out A+, so definitely aim for that. If you have no knowledge of ODE and are not sure what it'll be like, good luck; I suggest you take the class with a different teacher.
Do not take his class. I repeat: DO NOT TAKE HIS CLASS. I took this class because I thought it would be an easier way to learn ODE than taking the course in the math department. Boy, was I wrong. First off, you'll immediately notice the incapacity of Professor Fang to teach effectively. His lectures are fairly well structured, and would have some good information in them...if you could hear them. He lectures facing the chalkboard for the entire 75 minutes, turning around maybe twice to look for questions...but by that time, you'll be too confused scribbling down notes about concepts he hasn't fully explained to remember what you were gonna ask in the first place. His accent is thick enough that you will need to hear him say something a couple times before you actually figure out what it is. Trying to ask him for help after class is also useless...he'll just give you the same exact explanation he gave for that topic in class, so if you didn't get it then, you're definitely not gonna get it now. He also wears the same sweaters for months at a time. Lovely. And then came the tests. Each one that comes out gets progressively harder--he's not testing you on the course material so much as your ability to solve problems much harder than you've ever seen before in an unreasonably short time limit. The final was much, much harder than any of the homework problems--to the point where the actual answers were considerably more complex than anything I could have come up with. Isn't there an unwritten rule that answers on a math test should always come out somewhat neat? Not in Bohan's class. Despite all of this, I figured that since I did my homework, had done decently on the midterms, and only slightly worse on the final, I could still walk out of the class with a slightly disappointing, but acceptable final grade... ..and boy, was I wrong again. I don't think he curves this class at all...if anything, he probably curves against you. I got a full letter grade lower than I expected...and I really didn't think I was expecting much. And to believe he taught 2 out of the 3 sections of this course? Unbelievable. Columbia, I know you don't hire professors to teach, but this was absolutely absurd.
If this past semester is any indication, there's a good chance you'll be tempted to transfer out after the first lecture. Don't. Really, give him a chance. Sure, Professor Fang may look more like a student than a professor, and he may say things like "sabstraction" with a somewhat heavy accent, but if you can muster an ounce of patience, these trivialities become endearing rather than aggravating. By the second or third lecture, he starts sounding much less nervous, and you'll have no problem understanding his accent. He even cracks the occasional dry joke (or at least I think he was jokingâ€¦). Better reason to stay in Professor Fang's class: he makes his expectations very clear, and if you follow them and do all the work, you should be able to get an A. His teaching style may be rather bland (he pretty much walks in and writes on/talks to the blackboard for an hour and fifteen minutes straight), he really does explain the concepts well, giving the proofs for most theorems, and he rarely skips steps. He writes everything down, to the point that it almost becomes tedious, but chances are you'll appreciate this more than once during the semester when encountering a new concept. He answers questions patiently, but you have to speak up if you have one. Professor Fang only assigns about six moderate to challenging homework problems a week, giving you the freedom to do or ignore the "concept building" type problems at your leisure. This past semester, the exams in this course were all quite manageable (the first was a bit of a joke, really) and were, for the most part, easier than the homework. Professor Fang is a genuinely good guy who wants his students to do well. He'll stay after class to answer a question or help you out, he posts practice exams before both of the midterms and the final, and he goes over the practice exams in class during a "review lecture" before each exam. Give him a chance. And maybe sit toward the front at first.