e^(x+y)+xy=0两边对x求导得：e^(x+y)*(1+y')+y+xy'=0,解得：y'=-(e^(x+y)+y)/((e^(x+y)+x))=(xy-y)/(x-xy)e^(x+y)*(1+y')+y+xy'=0两边对x求导得：e^(x+y)*(1+y')^2+y''e^(x+y)+2y'+xy''=0解得：y''=-(e^(x+y)*(1+y')...