题目
题型:不详难度:来源:
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233027-25492.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233027-38183.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233028-84607.png)
(1)求数列
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233027-25492.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233028-41174.png)
(2)设
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233028-28844.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233028-74954.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233029-88746.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233029-39140.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233029-85923.png)
答案
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233029-75270.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233029-85923.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233030-15818.png)
解析
试题分析:(1)求数列
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233027-25492.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233028-41174.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233027-25492.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233030-60497.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233027-38183.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233028-84607.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233030-80471.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233030-58347.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233030-60497.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233031-80625.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233027-25492.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233028-41174.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233029-85923.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233028-28844.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233028-74954.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233029-88746.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233029-39140.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233028-74954.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233031-28801.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233031-92282.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233031-39834.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233029-88746.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233029-85923.png)
试题解析:(1)设
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233031-24719.png)
由
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233027-38183.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233037-76326.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233028-84607.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233037-93499.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233038-93798.png)
故
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233038-99816.png)
(2)∵
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233031-92282.png)
∴
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233038-69424.png)
由
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233029-88746.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233039-25800.png)
令
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233039-69318.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233040-17463.png)
核心考点
试题【已知公差不为0的等差数列的前3项和=9,且成等比数列 (1)求数列的通项公式和前n项和;(2)设为数列的前n项和,若对一切恒成立,求实数的最小值 】;主要考察你对等差数列等知识点的理解。[详细]
举一反三
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233012-95004.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233012-94047.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233013-57977.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233013-32225.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233013-78168.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233004-12797.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233004-43351.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233004-31923.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233005-69906.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011233005-98041.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011232947-49707.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011232947-28649.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011232947-52574.png)
A.![]() | B.![]() | C.![]() | D.![]() |
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011232937-59504.png)
A.1 | B.![]() | C.-2 | D.3 |
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011232923-41199.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011232924-27565.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011232924-97898.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011232923-41199.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011232923-41199.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011232924-97898.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011232924-27565.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011232923-41199.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011232923-41199.png)
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