2. Green's Theorem = Green's Theorem, which is that in theoretical physics, the study of potential energy and work has nothing to do with the path.
Key core theorem;
3. Generally speaking, integration along a certain path depends on the function of a specific path. As far as this topic is concerned,
On the whole, the product is from (0,0) to (1, t):
A, the first product from (0,0) to (1, 0)
Because y = 0, dy = 0, 2xydx = 0, Q(x, y)dy = 0,
So the integral from (0,0) to (0, 1) is 0;
B, multiply from (1, 0) to (1, 0).
Because x = 1, Q(x, y) was originally a function of x and y, now the integration starts from y = 0.
Product to y = t, and x = 1, that is, x remains the same. In this way, Q(x, y) degenerates into
Just a function of y, that is, Q(x, y) becomes Q( 1, y) and is written as C(y).
Do you understand? If you don't understand, please ask.