Hi, I am trying to solve something similar to ut = f(x,y), and ut = f(t,x,y) using RK4. I asked a few friends, and nobody knew for sure how to go about it. I've also looked online, without much success. Can anyone give me a hint on this one? In reality, it is probably preferable to derive a scheme from the first principle, but if I could avoid this, that would be nice. Thanks.