Go to class and take notes. He make this class like a lower division class. You can get an A without knowing anything and you will meet trouble in future study of differential geometry.

How can he teach differential geometry?
He is a funny professor but cannot teach.
His lecture is really interesting but useless.
He let TA grade the 2midterms(acceptable) but he told us he doesn't want to see the graded midterm and he doesn't know whether we understand his lecture and the problems given by him or not.
If you want to take a easy,interesting class , then choose him. But you won't get anything except some sense of humor after a quarter.
I just want to tell him that math is SCIENCE not a HUMOR.
As a ucla professor,please not to fool your students.

This was an interesting class. First of all, it is a class for pure math majors, yet they make math for teaching majors take it as well.

That being said, Petersen is a great professor. He is clear and concise about explaining the material. It was not Petersen I had a problem with, it was the material. Most math classes I have been able to idly sit by and not study too much until the final...but this one really whipped me into shape. The HW grader was extremely harsh, so most people got between a 5 and a 7 on all homeworks.

If you put a good deal of work into the class, it is easily manageable. He gives reviews before each test and recommends which problems you study from the homework before each exam...I'd say from the 10 questions on the final, 3 were on a final review sheet, 2 were from homework, 3 were simple applications from what we'd seen in class, and there were 2 harder questions.

If you don't have to take 120a, then do not, by any means, take it. However, if it is required for your major, take it with Petersen. Just prepare for a hard-working quarter.