※ 引述《plowsavior (咕噜咕咕)》之铭言： : Using Green's theorem to evaluate the line integral : 2 : ∫(y - 8y)dx + (2xy + 8x)dy : c : If C is the circle : 2 2 : x + y =1 by Green's Theorem 2 ∫(y - 8y)dx + (2xy + 8x)dy c = ∫∫[ (2y+8) - (2y-8) ] dxdy = 16 ∫∫dxdy = 16(pi)