Hi, For my math methods 3 course, I am not quite sure which books to use. The course is based on the math methods book by Riley, Hobson, and Bence, and I don't particularly like it. Hence, I am looking for some alternatives. Especially for the Preliminaries section. I had a real hard time doing the problem sets for that part, and I didn't know where to find resources to properly learn this. For the rest of the course, which is Complex Analysis, Fourier Series and Transforms, ODEs, and PDEs, I suspect Boas should work. I've attached a file with the aforementioned Preliminaries section. Thanks!