题目
题型:不详难度:来源:
![](http://img.shitiku.com.cn/uploads/allimg/20191015/20191015040940-48969.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191015/20191015040940-24548.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191015/20191015040940-96969.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191015/20191015040941-89228.png)
(1)求
![](http://img.shitiku.com.cn/uploads/allimg/20191015/20191015040940-96969.png)
(2)求数列
![](http://img.shitiku.com.cn/uploads/allimg/20191015/20191015040940-48969.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191015/20191015040941-80787.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191015/20191015040941-19012.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191015/20191015040941-59702.png)
(3)求数列
![](http://img.shitiku.com.cn/uploads/allimg/20191015/20191015040941-10247.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191015/20191015040941-19012.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191015/20191015040941-66386.png)
答案
![](http://img.shitiku.com.cn/uploads/allimg/20191015/20191015040941-13604.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191015/20191015040942-89497.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191015/20191015040942-96130.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191015/20191015040942-48104.png)
解析
试题分析:解:(1)∵数列
![](http://img.shitiku.com.cn/uploads/allimg/20191015/20191015040942-80583.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191015/20191015040940-96969.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191015/20191015040942-76831.png)
所以
![](http://img.shitiku.com.cn/uploads/allimg/20191015/20191015040942-89130.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191015/20191015040941-13604.png)
(2)由此知
![](http://img.shitiku.com.cn/uploads/allimg/20191015/20191015040942-89497.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191015/20191015040942-96130.png)
(3)令
![](http://img.shitiku.com.cn/uploads/allimg/20191015/20191015040942-35146.png)
则
![](http://img.shitiku.com.cn/uploads/allimg/20191015/20191015040943-70101.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191015/20191015040943-17975.png)
点评:本试题主要是考查了等差数列的通项公式和求和 运用,体现了裂项法求和的运用,属于基础题。
核心考点
举一反三
![](http://img.shitiku.com.cn/uploads/allimg/20191015/20191015040925-97829.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191015/20191015040925-40100.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191015/20191015040926-83859.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191015/20191015040926-80894.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191015/20191015040926-17857.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191015/20191015040926-94158.png)
A.0 | B.1 | C.2 | D.3 |
![](http://img.shitiku.com.cn/uploads/allimg/20191015/20191015040910-75302.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191015/20191015040911-14887.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191015/20191015040911-52931.png)
(1)设
![](http://img.shitiku.com.cn/uploads/allimg/20191015/20191015040911-36497.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191015/20191015040911-93222.png)
(2)求数列
![](http://img.shitiku.com.cn/uploads/allimg/20191015/20191015040910-75302.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191015/20191015040904-11823.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191015/20191015040853-89893.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191015/20191015040833-54290.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191015/20191015040833-36850.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191015/20191015040833-54290.png)
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