题目
题型:不详难度:来源:
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080813-10811.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080814-23902.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080814-39368.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080814-99453.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080814-64793.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080815-27929.png)
A.![]() | B.![]() | C.![]() | D.![]() |
答案
解析
试题分析:利用等差数列通项公式、性质、前
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080814-23902.png)
方法一
设等差数列
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080816-89310.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080816-48520.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080816-54268.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080816-27560.png)
所以
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080817-38221.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080817-57436.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080817-65342.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080817-95911.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080818-68664.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080818-30845.png)
方法二
设等差数列
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080816-89310.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080816-48520.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080816-54268.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080818-18121.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080818-10624.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080819-19910.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080819-31764.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080819-19184.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080819-32491.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080814-23902.png)
点评:解决此类问题的关键是掌握等差数列通项公式及性质、前
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080814-23902.png)
核心考点
举一反三
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080804-58181.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080805-95598.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080804-58181.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080805-22376.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080749-36332.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080750-48309.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080750-93653.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080750-12840.png)
(Ⅰ)求数列
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080749-36332.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080750-48309.png)
(Ⅱ)记
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080750-20232.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080750-45745.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080751-73607.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080750-45745.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080743-73521.png)
A.22 | B.18 | C.20 | D.13 |
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080735-13737.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080735-20218.png)
(Ⅰ)求
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080735-13737.png)
(Ⅱ)调整数列
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080735-13737.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080736-82539.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080736-58566.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080736-58566.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080736-17916.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080723-42801.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080724-70904.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080724-49980.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080724-65077.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080724-62580.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080725-44437.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080725-34027.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080725-74507.png)
(Ⅰ)求证:数列
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080723-42801.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080723-42801.png)
(Ⅱ)设
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080725-93593.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080725-11451.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080724-65077.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080726-52363.png)
(Ⅲ)设
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080726-18578.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080726-39888.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080725-74507.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080726-39888.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080725-74507.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191012/20191012080726-51257.png)
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