If a differential form $A(x,y)dx+B(x,y)dy$ is exact I know that exist a potential function that has $\frac{d(U(x,y)}{dx}=A(x,y)$ AND $\frac{d(U(x,y)}{dy}=B(x,y)$.
So now I know that $\int_{\alpha} (\omega) = \int_a^b \frac{dU(x,y)}{dx} x'(t) + \frac{dU(x,y)}{dy} y'(t) dt = \int_a^b \frac{d(U(x(t),y(t))}{dt}dt = U(\alpha (b)) - U(\alpha (a))$
My problem is: I can't see that intuitively.
I see that all passages are correct and so the result is correct, but I could never have done it because I don't see the intuition behind this generalization!