1 . 设数列
是一个公差不为零的等差数列,
.
(1)当
时,请在数列
中找一项
,使得
成等比数列;
(2)当
时,正整数
,且
,使得
成等比数列,求
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7b83d73d014a0ca4aff4282228312f55.png)
(1)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6df1038200f2d97a52c716aab6c3bcb6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/94e557d8ccd35f5a83b814aea04e17c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7ca337933edf8b0f5e44e0078374008.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fb334e165679c6cb500c994cffa47147.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1acff66c23432bfa8c8aeb233691695.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c698c0b3d1aa664d9571ea407d5ec77a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/820305fa45b15fb66d0246e50c076196.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1073aaf846f7b51ca1b7e706fd4486de.png)
您最近一年使用:0次
2 . 等差数列
中,
,公差
,
,求最大的正整数n,使
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9758d7707198a643d1ac091f3dda6eff.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/390636a89883bd64bf8da9bf8654aff9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2d8bbb4a09e0ac86bbae46222a90841.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df7cc5929edaef532bab13034333c795.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49763402b2f2023f0ba64c37924267d3.png)
您最近一年使用:0次
解题方法
3 . 已知正项数列
满足
.记数列
的前n项和为
,求
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/26bc610ffecf5f6c6eb49fbd601dda6e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b34e1d5ec76e6072d1636f5612958ba.png)
您最近一年使用:0次
名校
4 . 记
为等比数列
的前
项和,
,
.
(Ⅰ)求
的通项公式;
(Ⅱ)已知
,求
的最大值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2cdf53108bee755f5aa9a34ea4d163e4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2676bb9f41e0768b359a34c67eb0ad1d.png)
(Ⅰ)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
(Ⅱ)已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b25a7135aebae205a7ff2b0336d6087a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
您最近一年使用:0次
2019-01-02更新
|
815次组卷
|
4卷引用:【校级联考】安徽省示范高中培优联盟2018-2019学年高一下学期春季联赛数学(文)试题