设数列
的前
项和为
,且
,
.
(1)设
,求证:数列
为等比数列;
(2)设数列
的前
项和为
,求
.
![](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/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b065334d8f60c49f4bd3d9f1373fe4cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/903f7fe4e49590bfa9bb9fda46269972.png)
(1)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c4867dfd2b1fa71e386275fe0fed234.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
(2)设数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/846fa57d92d6ad44d6a0cafad1e71ed4.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/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
更新时间:2019-10-22 11:06:40
|
相似题推荐
【推荐1】已知数列
的前n项和为
,
,且
,
.
(1)在下列问题①②中选择一个求解;
①求证:
是等比数列,并求
;
②求证:
是等差数列,并求
.
(2)设
,
,若
是等比数列,求λ的值.
注:如果选择多个问题分别解答,按第一个解答计分.
![](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/039e4fe671d61e59b96ee525c9df43e8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a2c88d061879b5fa3a9f7cea86d5204d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f093c61867ee4ce75f951d46b9b123.png)
(1)在下列问题①②中选择一个求解;
①求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b2c1c902dfa2488705732f1712e68963.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96abfe2da27a63e6affb19a0c80236d9.png)
②求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/40dc43b8d11d5462e4b525dd7b03bcfc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96abfe2da27a63e6affb19a0c80236d9.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3894eab7dff4a5d2e4d09f8ee8ff38bd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/13e87088da41685cc8d433fbbe0e18d6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
注:如果选择多个问题分别解答,按第一个解答计分.
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解答题-证明题
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解题方法
【推荐2】数列
满足
,
,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cea4ac187cbb465180e89f38250b3970.png)
(1)求证:数列
为等比数列
(2)是否存在互不相等的正整数
,
,
,使得
,
,
成等差数列且
,
,
成等比数列?若存在,求符合条件的
,
,
,若不存在,说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cc6545b8eca1c4223ed701a199a85683.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7643e8b7aa32ebf299048417a94432dc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cea4ac187cbb465180e89f38250b3970.png)
(1)求证:数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/213e22890204937a5dded4436369390f.png)
(2)是否存在互不相等的正整数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5873c01192b7d33b7483f444f90b5b0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36a1b09c653185842513e24ebba60bb3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5873c01192b7d33b7483f444f90b5b0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36a1b09c653185842513e24ebba60bb3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb10dd730b827d3ec05aebe8c18c9e4c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2ff1721a696504d02a4c4b20e5ba7f02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a4d466d07fa48ce8323be14480fe108.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5873c01192b7d33b7483f444f90b5b0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36a1b09c653185842513e24ebba60bb3.png)
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名校
解题方法
【推荐1】“绿水青山就是金山银山”,中国一直践行创新、协调、绿色、开放、共享的发展理念,着力促进经济实现高质量发展,决心走绿色、低碳、可持续发展之路.新能源汽车环保、节能,以电代油,减少排放,既符合我国的国情,也代表了世界汽车产业发展的方向工业部表示,到2025年我国新能源汽车销量占总销量将达20%以上.2021年,某集团以20亿元收购某品牌新能源汽车制造企业,并计划投资30亿元来发展该品牌.2021年该品牌汽车的销售量为10万辆,每辆车的平均销售利润为3000元.据专家预测,以后每年销售量比上一年增加10万辆,每辆车的平均销售利润比上一年减少10%.
(1)若把2021年看作第一年,则第n年的销售利润为多少亿元?
(2)到2027年年底,该集团能否通过该品牌汽车实现盈利?
(实现盈利即销售利润超过总投资,参考数据:
,
,
)
(1)若把2021年看作第一年,则第n年的销售利润为多少亿元?
(2)到2027年年底,该集团能否通过该品牌汽车实现盈利?
(实现盈利即销售利润超过总投资,参考数据:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08de74a2aea3fea51fbf9e4b9e6803d0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6090adebcc1f431e01196d6ccad0568a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7e6c3fdee8ea7588d60b8342e457e8e0.png)
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适中
(0.65)
【推荐2】已知数列
前
项和
.数列
满足
,数列
满足
.
(1)求数列
和数列
的通项公式;
(2)求数列
的前
项和
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/12e82f82ea3a90feeaf8d603859fb670.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/787c464360e067294168f7613a80befd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57ef6d44448092ebdb9e4a49d866a749.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac07953530e3c248b3438fb200fb1661.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
(2)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57ef6d44448092ebdb9e4a49d866a749.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
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