x（y^2）- e^xy + 2 = 0\r\n\r\n两端同时求导：\r\n(y^2 + 2xy'y) - e^xy(y+xy') = 0\r\n集项：\r\n(2xy - xe^xy)y' = (ye^xy - y^2)\r\n则：\r\ndy\/dx = y' = (ye^xy - y^2)\/(2xy - xe^xy)