(x3 + xy2)?dx + (x2y + y3)?dy = 0x(x2 + y2) + y(x2 + y2)?dy/dx = 0(x2 + y2)(x + dy/dx) = 0x2 + y2 = 0 或 x + dy/dx = 0y dy = - x dxy2/2 = - x2/2 + Cy2 = - x2 + Cx2 + y2 = C所以通解为x2 + y2 = 0 或 x2 ...? 是什么意思啊不小心多加了~~不要就可以.