令y=[1-(2/x)]^(x+2)lny=ln{[1-(2/x)]^(x+2)}
=(x+2)ln[1-2/x]
=ln(1-2/x)/[1/(x+2)]当x->无穷分子1-2/x->1,ln(1-2/x)->0分母1/(x+2)->00除0，得用洛必达法则分子求导=[1/(1-2/x)]*2/x^2=2/(x^2-2x)分母求导=-1/(x+2)^2所以ln y 极限=[2/(x^2-2x)]/[-1/(x+2)^2]=-2(x^2+4x+4)/(x^2-2x)上下同除x^2=-2(1+4/x+4/x^2)/(1-2/x)当x->无穷，lny->-2*(1+0+0)/(1+0)=-2所以y->e^(-2...
