说明：因为无穷乘无穷=无穷,所以无穷乘无穷的题目就等于无穷.原题能做出来.
原式=lim(x->0+)[(lnx)²/(1/x)]
=lim(x->0+)[(2lnx/x)/(-1/x²)](0/0型极限,应用罗比达法则)
=lim(x->0+)[(2lnx)/(-1/x)]
=lim(x->0+)[(2/x)/(1/x²)](0/0型极限,应用罗比达法则)
=lim(x->0+)(2x)
=2*0
=0.