lim[x^(1/x)-1]^(1/lnx)=e^limln[x^(1/x)-1]/lnx罗比达法则=e^lim[1/(x^1/x -1)*(x^1/x)']/(1/x)因为x^1/x 化为自然对数求导后可得x^1/x=x^1/x *(1-lnx)/ x^2又因为limx趋向无穷大时x^1/x -1 =e^lnx/x -1 ~lnx/x 也可得limx^1/x =1代入=e^limX^1/X *(1-lnx)/x(x^1/x-1)=e^lim1 * (1-lnx) / x* lnx/x=-1既=e^-1