题目
题型:不详难度:来源:
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162703-99041.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162703-88866.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162704-13995.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162704-56205.png)
(1)若
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162704-38749.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162704-31776.png)
(2)是否存在
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162704-31776.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162704-13995.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162705-27740.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162705-29998.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162705-93876.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162704-31776.png)
答案
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162705-32209.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162704-31776.png)
解析
试题分析:(1)由前n项和求通项,根据
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162703-88866.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162706-70784.png)
代入求得
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162706-41516.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162704-38749.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162707-25502.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162704-31776.png)
(2)先假设存在
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162704-31776.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162705-29998.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162705-93876.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162707-51963.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162707-46235.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162707-76050.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162707-85311.png)
试题解析:
(1)因为
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162703-88866.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162708-23905.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162708-26331.png)
又当
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162708-43781.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162708-49521.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162706-70784.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162706-41516.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162708-53219.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162707-25502.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162709-98336.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162709-14085.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162705-32209.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162705-32209.png)
(2)假设存在
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162704-31776.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162705-29998.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162705-93876.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162707-51963.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162707-46235.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162707-76050.png)
所以当m-5=1,2,3,4,6,9,12,18,36时,分别存在t =43,25,19,16,13,11,10,9,8适合题意,即存
在这样m,且符合题意的m共有9个.
核心考点
试题【设数列的前n项和,数列满足.(1)若成等比数列,试求的值;(2)是否存在,使得数列中存在某项满足()成等差数列?若存在,请指出符合题意的的个数;若不存在,请说明】;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/20191011/20191011162633-12529.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162634-63295.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162634-63547.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162634-77289.png)
(1)求
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162634-50197.png)
(2)求数列
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162633-12529.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162634-58626.png)
(3)设数列
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162635-40803.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162635-47221.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162635-59860.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162636-14874.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162635-47221.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162636-20175.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162626-51827.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162626-38708.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162627-80432.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162627-58116.png)
A.![]() | B.![]() | C.![]() | D.![]() |
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162620-94008.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162620-94442.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162620-30315.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162620-30315.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162620-94008.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162620-12661.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162621-78864.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162621-21373.png)
A.10 | B.100 | C.200 | D.400 |
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162431-83671.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162432-45985.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162432-23744.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162432-25694.png)
A.![]() | B.![]() | C.![]() | D.![]() |
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162424-87806.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162424-91030.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191011/20191011162424-54243.png)
A.24 | B.22 | C.20 | D.-8 |
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