limxn=0,limxn+1/xn=a,证明|a|≤1

题目

limxn=0,limxn+1/xn=a,证明|a|≤1
lim(xn)=0,lim((xn+1)/(xn))=a,证明|a|≤1

答案

if for some n,|xn|>1,then |xi| keep growing from then on.
so |a|≤1