lim (x^x-x)/(lnx-x+1)
=lim ((lnx+1)x^x-1)/(1/x-1)
=lim [(1/x)x^x+(lnx+1)²x^x]/(-1/x²)
=(1+1)/(-1)
=-2
＝＝＝＝＝＝＝＝＝＝＝＝
连续用了两次洛必达法则