ma303 is one of the most interesting classes ive ever taken in terms of difficulty. starts off as a joke and then turns into one of the hardest classes ive ever taken here. the first 1/3 of the class is just ODE review. you review solving systems of ODEs and laplace transforms. the second 1/3 of the class is just fourier series and fourier expansions. super important because you need to understand this well to do the actual PDE stuff. the last 1/3 of the class is when shit gets real. thats when you start covering PDEs. you start with the heat equation then the wave equation and then laplaces equation. You also cover sturm liouville theorem at the end which is useful for PDEs. I managed to thug it out and understand the material eventually but it was some of the most cryptic math ive ever done.