This is the problem I just worked through. My problem is that, although I can't see any error, it seems to have worked out to neatly. Is this right?
Also, although I just did the work, I don't really understand what it means. If the answer is zero, does that mean the flux of a fluid on this vector field is zero? Meaning that it is not moving at all? Or that the same exact amount is coming out as is going in?