设数列
的前
项和为
.
(1)若
(
),
,且
递增,求
的取值范围;
(2)若
,
,求证:
.
![](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)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/39368d40098ad7432d5e09185f74c1be.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d6420a7bdf9eb4421eb9e3cd68e846d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cea4ac187cbb465180e89f38250b3970.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1010846eeec6c9da29640f5aa3f8738.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0be1405762321a08a6e47b34c9b175d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d547b100cbbd6758800472797edcbfa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e3273bc4cf5ff9d0cda2e90cdfc84085.png)
更新时间:2020-09-06 23:28:06
|
【知识点】 前n项和与通项关系
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解答题
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较难
(0.4)
【推荐1】已知Sn是数列{an}的前n项和,且an=Sn-1+2(n≥2),a1=2.
(1)求数列{an}的通项公式.
(2)设bn=
,Tn=bn+1+bn+2+…+b2n,是否存在最大的正整数k,使得
对于任意的正整数n,有Tn>
恒成立?若存在,求出k的值;若不存在,说明理由.
(1)求数列{an}的通项公式.
(2)设bn=
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2cc19bd370858782426f32566b84cc35.png)
对于任意的正整数n,有Tn>
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2e37a1ebab735e1d53c9e36625e9955.png)
您最近一年使用:0次
解答题-证明题
|
较难
(0.4)
【推荐2】已知数列
的首项
,前
项和为
,且![](https://staticzujuan.xkw.com/quesimg/Upload/formula/41492660eeec539a15cba234e24a8209.png)
(Ⅰ)求证数列
为等比数列;
(Ⅱ)设数列
的前
项和为
,求证:
.
(Ⅲ)设函数
,令
,求数列
的通项公式,并判断其单调性.
![](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/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/41492660eeec539a15cba234e24a8209.png)
(Ⅰ)求证数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e2de706dc5f0439b989273a5367f63a.png)
(Ⅱ)设数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/41cf1da18d91f7c98086553d157d1a87.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/06e4a6bddcc520e62f713f9ab6ac1e38.png)
(Ⅲ)设函数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d45ee0aae5f32cbcdb73e8bfeddebacb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24b5f0ef8aa177e9ef73e3ae47498d78.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
您最近一年使用:0次