1 . 已知数列
的通项公式
,则
( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f448cebfaf66b70a4c8485bde0398d3e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5fb23c6a9e8a42faef0a84be8ad6b008.png)
A.99 | B.100 | C.101 | D.102 |
您最近一年使用:0次
2 . 已知
,则数列
一定是
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6b211419ca215ea5f4687cd8de299d6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
A.等差数列 | B.等比数列 | C.递增数列 | D.等差数列又是等比数列 |
您最近一年使用:0次
3 . 已知等差数列
满足
,
.
(1)求数列
的通项公式;
(2)令
(
),问数列
是否有最大项或最小项,若有,请求出最大项或最小项;若没有,请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fe229b24e2d56ff6b491725ceae4ff2f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f883388e60eb4893b32c9cd46d0e6dee.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/77742c88956b44e885c8ae168df9a59a.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fe229b24e2d56ff6b491725ceae4ff2f.png)
(2)令
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f5b5cdfb9a2148188c5059fcb7c46c61.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e1f5f8ff937a04630962d3e391b6073.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bee4464b3b4eb6e52ee02f095aae84f0.png)
您最近一年使用:0次
4 . 已知数列
的前
项和
满足:
.
(Ⅰ)求数列
的通项公式;
(Ⅱ)若
,数列
的前
项和为
,试问当
为何值时,
最小?并求出最小值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/12e4558b32b33a3dbb72c8b64d94f273.png)
(Ⅰ)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(Ⅱ)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e9645bd4d2002993b90ec6d48f9c04f7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/005bdc007e32252bb47104c7f5f9faa6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
您最近一年使用:0次