已知等比数列
的公比为
,前
项和为
,
,且
是
与
的等差中项.
(1)求
的通项公式;
(2)设
,
的前
项和为
,证明:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09e15be6eb86b5f1746b0036a87c9ca7.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/964df3e9308711d7e14fb624b0c25e2f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/911278aa8595846abac1972e1de59995.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e86e2e42b4aa93db9241103e7f61766c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9a37f1b45e929b42044626edb63681fb.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d9d22787faf3cab18b8fa922cc485008.png)
![](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/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6bda0b0b170a4c01c55b6888e5513ebe.png)
更新时间:2021-05-17 18:25:29
|
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解答题-问答题
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适中
(0.65)
解题方法
【推荐1】已知无穷数列{an}中,a1,a2,…,am是首项为2,公差为3的等差数列,am+1,am+2,…,a2m是首项为2,公比为2的等比数列(其中m≥3,m∈N*),并对任意的n∈N*,均有an+2m=an成立.
(1)当m=14时,求a1000;
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(1)当m=14时,求a1000;
(2)若a52=128,试求m的值.
您最近一年使用:0次
【推荐2】已知等比数列
的前n项和为
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恒成立,
,
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(1)求数列
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;
(2)设
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef64850887c5c8cad4d574b0b09307a9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c0863cf59114f905e9ad3debc5572792.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4ccdc17b603871d20843ffccca2df0ae.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b00f934ec9aa1208cb375e7559070880.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f8a6c48963c5e6f2e9f412d08c49469.png)
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解答题-证明题
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适中
(0.65)
【推荐1】在数列
中,
,
(
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是常数).
(1)当
,
时,求数列
的通项公式;
(2)当
,
时,设
,求证数列
是等比数列;
(3)在(2)的条件下,记
,
,求证:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b13a6e1d671215fc96e4bee3541d1096.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c1f4702282b8a6fc12bd46d89aff3ca6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/071a7e733d466949ac935b4b8ee8d183.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5c02bc0c74292b1e8f395f90935d3174.png)
(1)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4580cc037c0c760c728cdbb74a8154c6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ae3012337aa392709349731fb1eef5b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6de1d395e6c48c0676a1488a299479d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60acf58bad78854a0db851c42f739543.png)
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
(3)在(2)的条件下,记
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/215f14cdf94bb76da59e7192cf0f3944.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9cd158b82679511af01fea146a5e2b74.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b2905b0ba7e89d825a87f4fec1b5e38a.png)
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适中
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解题方法
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
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(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fd7d90f6cd670824b1acb402fc125ad5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
您最近一年使用:0次
解答题-证明题
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适中
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【推荐1】已知数列
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求证:
,
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/29518f13a1ebc3fff8181c2d7cfba22f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/90fa45d99faf476e983cd7d31a402135.png)
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【推荐2】已知等差数列
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/216876de04325fd250c38c485cbc34b7.png)
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/812c9734b098c19b593b9d1b89f8951b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
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