1. The problem statement, all variables and given/known data Last week we've been doing partial derivatives and I understood all that , but also skipped last lecture.I asked colleague about the lecture and he told me that professor mentioned something about rotor and he gave an example of such and such problem.Anyway here it goes: 1)Prove that the expression (something)dx+(something)dy+(something)dz is a differential of a function and find that function. 2)Find u(x,y,z) if du=(something)dx+(something)dy+(something)dz You get the picture. Now I've looked up about the rotor stuff and found it has something to do with vector fields.So I tell that to my friend but he says lecturer didn't even mention anything like that, he says they used integrals on multivariable functions and so on. Where I can find out more about these types of problems? What to look for in textbooks? Thanks. 2. Relevant equations / 3. The attempt at a solution I don't know what to look for.