Professor Arnold is a really nice guy and he puts a lot of efforts into teaching. He genuinely cares about his students and he is really helpful during office hours. His lectures are engaging and he has a good sense of humor. He doesn't do many examples in class and most of the time, he just goes over the definition/concepts. I wish he did more examples in class. He covered dimensional analysis, perturbation theory, traffic flow and population theory. Since he doesn't do many examples in class, I definitely spent more time on my homework. I guess 142 is not an easy class and you really need to put in more efforts. Wish I realized that before my final :( Overall, it's a good class and you will learn a lot from it.

I had Arnold for Math 32A and I loved having him as a professor. He comes off as kind of shy and quiet but he's very funny and does a fantastic job of explaining the material. Both midterms were fairly easy and the final had two "curve-setting" questions that were difficult for most people. His homeworks are also really short (3/4 problems per week) but they make you think about the material in a critical way. Overall, I definitely recommend Arnold as a professor, but make sure to put in a lot of effort to do well.