Winter 2023 - Taking this class is very like a roller coaster. The beginning about Fixed Point and Contraction Mapping is easy, if you took 131AH and has the topology mindset. The second part -- about Inverse Function Theorem and multivariable derivatives -- is hard, because the dense proof presented here, and the frequent use of linear algebra. The third part is about Winding Numbers -- a very interesting topological invariant that gives you a taste of homotopy in algebraic topology. I think this is the most beautiful part of the course (also most geometric and topological). The last part is about Riemann integral and Fourier Series, which are I believe the easiest section of the course. In general Professor Greene took a very intuitive path to lead you down into the world of differential analysis through powerful topological mindset developed in the previous course. Strongly recommend to take if you wish to enjoy the beauty of mathematics.
Winter 2022 - Prof Greenfeld cancelled our midterms so we had no idea how her exams worked going into our final, and homeworks and final were graded incredibly harshly, forcing us to write out every step for basic integrals we know from 31b or proving results shown in discussion. Do not take this class unless you want to spend 11 hours on a final exam and have it nitpicked till there is nothing left.
Spring 2021 - After taking Math 131ABH with professor Visan, I can confidently say that she's (one of) the best math professor I've ever had; her lectures are extremely clear, and homework assignments are helpful for us to truly understand our content. Also, she's always willing to help us when we get stuck on our homework problems. However, be careful about her finals; the 131AH final she gave was more difficult comparing to homeworks and midterms that quarter, and the 131BH final was terribly difficult. But this still doesn't affect the fact that she's an excellent professor.