题目内容
设数列{xn}满足log2xn+1=1+log2xn,且x1+x2+x3=7,则x4+x5+x6=__________.
答案:56
解析:∵log2xn+1=1+log2xn=log22+log2xn=log22xn,
∴xn+1=2xn.
故{xn}是以2为公比的等比数列,∴x4+x5+x6=23(x1+x2+x3)=56.
练习册系列答案
相关题目
题目内容
设数列{xn}满足log2xn+1=1+log2xn,且x1+x2+x3=7,则x4+x5+x6=__________.
答案:56
解析:∵log2xn+1=1+log2xn=log22+log2xn=log22xn,
∴xn+1=2xn.
故{xn}是以2为公比的等比数列,∴x4+x5+x6=23(x1+x2+x3)=56.