名校
1 . 已知
是等差数列,
是公比不为
的等比数列,
,
,
,且
是
与
的等差中项.
(1)求
和
的通项公式.
(2)求![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d46e92ff41a3037a51bf594df6f73bc3.png)
(3)若
,证明:
.
(4)数列求和问题的关键是根据通项公式特点找到适合的求和方法,并进行合理变形,观察下列数列通项公式特点,填表:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdaa19de263700a15fcf213d64a8cd57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7def23f30138e0b7c4c1e498d6903a6c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a8ec38ab7e6912bcc97513a359bd5e1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1320e2e9d9c398ec700482b06153d05b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c7e82778985cd2e9f80ca7b7cabb1a85.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9632e7e5a6eb0c85cb44940c60618d67.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57483e04fd1840c87ac5325157149877.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d46e92ff41a3037a51bf594df6f73bc3.png)
(3)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9169c81b9643e9dcd5c945d580186c97.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e06ae105393888c9e02fb2437428217c.png)
(4)数列求和问题的关键是根据通项公式特点找到适合的求和方法,并进行合理变形,观察下列数列通项公式特点,填表:
通项公式 | 求和方法名称 | 变形成可求和形式 |
![]() | ||
![]() | ||
![]() |
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