解题方法
1 . 已知数列
,
,
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/00394586e9de0a62b05676088c27116f.png)
____ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b065334d8f60c49f4bd3d9f1373fe4cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/74359aafdc9f61d305ce01888188ecaa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/00394586e9de0a62b05676088c27116f.png)
您最近一年使用:0次
2 . 在数列
中,
.
(1)求证:数列
是等比数列;
(2)设
,求数列
的前
项和
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d737c1047a14cee12a6671383e244fa5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/28d8c6a8f726e7041e7195386c4c8d8a.png)
(1)求证:数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf62534674a87088c8366e5c25888638.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/43a454ec969d0c8b221a06895f79f710.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a89d1f32c1605cfdb8e8855051b9f6ec.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
您最近一年使用:0次