Professor Fronsdal, unless you feel pretty confident about physics in general, is a very difficult teacher in that his lectures are not very helpful. You would think the examples he goes over in lecture would help but you soon realize there is no real purpose in showing up cause the problems on the test are way different. He tries to be fair and he does care (there is no doubt). But because hes not very good at explaining things--its gonna be harder for you. Overall, hes like any physics teacher--not very good. So you would think it should be easy to handle. The problem is that both his TA's are horrible. One takes forever in solving a problem and the other is practically apathetic to getting the message across. This made the class harder than it should have been. The only good thing is that his midterms are 10% each and HW is 30%. Just watch out for the final--thats the main factor in your final grade. The only advice I got if you're taking him for a lower div, get a lot of friends who are good in teaching physics.
His lectures are conceptual and so are most of the homework/test questions. His teaching... is a bit confusing (he switches notations or messes up a bit), but it's a good kind of confusion. It's the kind that makes you want to figure out what the heck is going on, and the kind that allows you see how a physicist SHOULD think. There is no doubt he actually cares about the students learning, but I'd guess that people in our class are a bit intimidated or something (or that he doesn't hear us ask questions sometimes). Also, he (or his graders) grade very leniently. The bottom line is, this guy is a genius, and his derivations (although many of you might hate those) are quite brilliant once you figure out his line of reasoning at the end. I hope he teaches again next quarter because I feel myself slowly learning to hone my intuition and generate physical interpretations from seemingly random equations.
I would not recommend Prof. Fronsdal. The two main problems are 1) the material and 2) communicating with him. 1) In 105B, he did cover what most 105B classes generally would cover: Hamiltonian mechanics, collisions and Conservation of Momentum, gravitation and Kepler's Laws, scattering theory, special relativity, 4-vectors. However, in about 3, 4 weeks in, he introduces group theory (from Math 110A) and attempts to review some concepts from linear algebra (while bungling up various definitions) and differential geometry (generators of infinitesimal translations, rotations, etc.). The class takes a turn for the worse from that point on. If you want to cover topics sufficiently for usage in other classes (such as scattering theory for Physics 126), then you're stuck resorting to the not-so-great textbook that Fronsdal only refers to once a week (Marion and Thornton, Classical Mechanics). 2) Communicating with him is a problem. He wears a hearing aid, and I know it can't be helped, but . I attended his office hours almost weekly for homework questions. He will answer nearly anything you throw at him, but you'll find yourself raising your voice to the point where the rest of the faculty in the PAB 4th floor theory cluster will hear you. This is even worse in class when people attempt to ask him questions, and it may take as many as 2, 3 minutes to get the whole question across before he starts to address it. In the past several quarters that he's taught this class (the 105AB sequence), I feel like the students were lucky enough to have decent/good TAs who knew their material well or would invest their own time to consult Fronsdal on any mix-ups or anything simply not understood, and relay the message back to the students. He has a very generous grading curve, but don't let that fool you into thinking you'll get that much out of the class otherwise.
If you want to do well in his class, you simply have to understand what he teaches. All his midterms and final are based on his notes and homework, and they are easy questions but covering difficult concepts. So if you don't understand him(lectures,notes,hw), there is no way you can do well on the tests. Everything he teaches is theoretical, there is barely anything to memorize in the class. Go to his office hours if you don't understand something, he will explain it in detail. He is available everyday after class, and a very nice person to talk with.
Professor Fronsdal is one of the very few teachers I have ever had who demonstrated such extraordinary caring for the success of his students. He is nearly always in his office and happy to have a pleasant conversation with any students who come by with a question. Complex Analysis is a very difficult and often subtle subject, but he succeeds in inspiring students to pursue it further rather than driving them away from it.