professor
Yannan Qiu

May 2011

I'm guessing that you could do a lot worse than Yannan Qiu for a Calc II teacher. He has a fairly thick accent, but it completely understandable, and his handwriting - no exaggeration - is possibly the nicest I've ever seen. Each lecture is based on a section or two from the book and feature a handful of examples/theories that he does a pretty good job of explaining (for the most part). Some of the examples are not as clear or concise, but I don't think that it affects how well you will understand the material - the most learning in the course, I think, comes from the problem sets. The problem sets are weekly, and tend to be quite long. The shortest was 9 problems, the longest an epic 21! For the most part, however, the sets are between 12-15 problems, usually taking a few hours to complete. There are 2 midterms in this class - the first about 6 weeks in and the second about a month later. The first is extremely straight forward and features questions that only ask you to integrate. The second midterm was a bit more difficult, and the averages indicated this. The final exam was extremely fair and straight forward, with 2/3 of the material coming from sections that were learned after the second midterm. A week before the exam he distributed a sample final which turns out to be a rough draft for the final - there are many of the same types of problems and even an exact problem or two. Qiu is a very nice guy, who is incredibly intelligent. I think he's pretty funny, too, but not because he tells jokes or anything like that. His hilarity comes from his interactions with students where he will occasionally giggle at a student's suggestion on how to solve a problem, all in good nature. Would suggest taking Calc II with this professor if you have to take this class.

Apr 2011

Though Yannan Qiu has a bit of an accent and Calc 2 is a notoriously aggravating class, Qiu was an amusing teacher, and always more than willing to answer student's questions. His explanations weren't always the most clear the first time, but it was easy to get him to reexplain theories and proofs. That being said, a re-explanation didn't necessarily clear up all confusion, but doing the homework was usually enough to solidify the ideas. There were also a number of funny moments in class, when he would make a mistake on the board or make a joke about something, usually his inability to pronounce students' names. It helps to sit near the front of the class to hear him, since as other reviewers mentioned he has a soft voice. He is very generous about grading on exams. It was easy to go to him and explain the intention of your work on a problem to garner some points, many times enough to raise the grade by a decent amount. He doesn't always understand where you were going on a problem if you reach the wrong answer, but it's definitely worth it to talk to him about it.

Mar 2011

He's an alright teacher. I didn't really learn much from him, but I think it's because of his teaching style. I found it hard to follow his lectures because it lacked direction. He would write examples on the board and start solving them and I'd have no idea where he was going with all of it. Also, I had it as a 9am class and combined with his soft voice and the fact that nearly everyone else was just as drowsy, I found it had to actually engage myself in the class. However, his tests and homework assignments are pretty straightforward. I still went to lecture, but I'm sure it wouldn't have mattered if I just studied the textbook instead. Every once in a while, he'll say something dorky or laugh awkwardly and the class will laugh, and it was be eye-opening because I never knew so many people actually paid attention to him.

Jan 2011

While Qiu has a somewhat thick accent that contributes to regular “disconnects” between him and his students, his English is nonetheless understandable for the most part. Be warned that if Qiu is short on time, he has a tendency to rush through his lessons without making sure that the class is on the same page. (Rushing through Calc II lessons) + (Somewhat thick accent) = Confusion Nonetheless, Qiu is very bright and immensely competent in the subject matter. In addition, he is an approachable guy who can be pretty funny (“The population will naturally go towards carrying capacity unless there is a war and people are killed”), and he really makes himself available to help his students. If you’re stuck on a problem, you can bet that Qiu would be more than happy to help you out and guide you to the solution; I have never seen Qiu stumped by a calculus problem. Even though he frequently regurgitates the Stewart textbook (which predictably leads to some people not showing up to class), I would highly recommend that you attend his lectures. A number of heavily proof-based topics that appear on his finals are outside the scope of the Stewart textbook. To get the most out of Qiu’s lectures, it may be a good idea to read the Stewart book first and learn the lecture material on your own before going to class. That way, you won’t be so confused. Calc II is a challenging class and Qiu may not be the best math professor at Columbia. But if you stay on top of the problem sets, do extra practice problems from the Stewart book, seek help from Qiu when you need help, and pay close attention in class, an A is totally doable (top 25% of class gets A’s). You can get a lot out of this class.

Dec 2010

This course is very challenging, and Prof. Qiu doesn't do much to help you except spend class time rewriting the text book examples on the chalk board. If you bombard him with questions you might stand a chance--he is very nice and helpful at office hours-- but for the most part the curve is what will save you. I would not really recommend this course, but if you're taking it it's because you need a requirement fulfilled anyway.

Dec 2003

Gee... where do I start? Professor Qiu's lectures are horrible - he makes everything so much more complicated with his graphs and drawings and mathematical symbols, plus his English abilities are very limited. If you have a good background in Calc IA, this is the class for you. You don't really have to go to class (by the end of the term, there were only around five people left at lectures). Just do each week's homework and you'll know what he taught, show up for the midterm and final, and you'll probably get a decent grade - he's a really nice grader. He says he doesn't give curves, but he also said that with around a 75 average on the tests, you could still get an A. On the other hand, if you never took Calculus before, DO NOT take this course!