已知各项不为0的等差数列{an}满足2a3-a72+2a11=0,数列{bn}是等比数列,且b7=a7,则b5b9=()A.2B.4C.8D.16-数学

题目简介

已知各项不为0的等差数列{an}满足2a3-a72+2a11=0,数列{bn}是等比数列,且b7=a7,则b5b9=()A.2B.4C.8D.16-数学

题目详情

已知各项不为0的等差数列{an}满足2a3-a72+2a11=0,数列{bn}是等比数列,且b7=a7,则b5b9=(  )
A.2B.4C.8D.16
题型:单选题难度:中档来源:不详

答案

根据等差数列的性质得:a3+a11=2a7,
2a3-a72+2a11=0变为:4a7-a72=0,解得a7=4,a7=0(舍去),
所以b7=a7=4,
则b5b9=a72=16.
故选D

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