lim [x-->0,y-->0] xy/(√(2-e^(xy))-1)分母有理化=lim [x-->0,y-->0] xy(√(2-e^(xy))+1)/(2-e^(xy)-1)=lim [x-->0,y-->0] xy(√(2-e^(xy))+1)/(1-e^(xy))分母用等价无穷小代换=lim [x-->0,y-->0] -xy(√(2-e^(xy))...