已知
是公差为3的等差数列,
是公比为2的等比数列,且
.
(1)求
和
的通项公式
(2)若数列
满足对于任意的
,且
.
①求
的通项公式;
②数列
满足
,求
.
![](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/e651aa13af7d55a1bebf11791c56764f.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
(2)若数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57ef6d44448092ebdb9e4a49d866a749.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c97c2b746d7f363c7b3739a46e7a8e7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/43bb67cf8df57986da087b0b1dd3ffd6.png)
①求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57ef6d44448092ebdb9e4a49d866a749.png)
②数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/272b44a71d0bec02b3c4f3f05304f942.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3341a3b9b1e614a7587e51f3076f084b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/785bb3d13678a572f1d43ec6594944b5.png)
2022·天津南开·模拟预测 查看更多[2]
更新时间:2022-05-23 09:54:22
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解答题-问答题
|
适中
(0.65)
解题方法
【推荐1】已知
为等比数列,
分别是下表第一、二、三行中的数,且
中的任何两个数都不在下表的同一列,
为等差数列,其前
项和为
,且
.
(1)求数列
的通项公式;
(2)若
,其中
表示不超过
的最大整数,如
,求数列
的前80项的和
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/97c14d9ae06f864498048d55088ff4e6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/97c14d9ae06f864498048d55088ff4e6.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/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/82b56a1be4e00d9ef049c7ff07558ecc.png)
第一列 | 第二列 | 第三列 | |
第一行 | 1 | 5 | 2 |
第二行 | 4 | 3 | 10 |
第三行 | 9 | 8 | 20 |
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/62e567d7e9761951a266953c8d5042ac.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4ebe2da2c5838f74adee64e18aa9a752.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c4f5908d6a1217e493ed7586b6964dd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6736241d60d47c77141741d75ac2f854.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57ef6d44448092ebdb9e4a49d866a749.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bb2fed4e1a52429fb7eb78148b9dcf8b.png)
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解答题-问答题
|
适中
(0.65)
【推荐2】已知等差数列
的公差不为零,
,且
,
,
成等比数列.
(1)求数列
的通项公式;
(2)若
,求数列
的前
项和
.
![](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/3e88093a749c0d46e0ee931ecfaff925.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f65fc200f10b97588a0c9896277c9c64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/46be9c9b05fd84ac9256d49a5a553af5.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dc78188e7f5a33a1c38f0cd186e33d7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2d51f9147b8265c0276c1f2c2659197.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3b9a0d7150fb24be3e28ef7f0e18be93.png)
您最近一年使用:0次
解答题-问答题
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适中
(0.65)
【推荐1】设等比数列
的前
项和为
,已知
,且
成等差数列.
(1)求数列
的通项公式;
(2)若数列
是首项为
,公差为
的等差数列,求数列
的前
项和
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/29518f13a1ebc3fff8181c2d7cfba22f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b708c8dcb2d66eb2ce0b3718a9cd924a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/663bbc5767b9cb453cb08e1f0a8e0602.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ef889d99e4af3ebc20e23c56d49a214.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/29518f13a1ebc3fff8181c2d7cfba22f.png)
(2)若数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df3f2d74acb3a4b3ce20297aeb926de6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdaa19de263700a15fcf213d64a8cd57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2448cf72af76b810310e4cfb9818e2e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb26cd1601fe7e76e1e2dc0b4909324a.png)
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【推荐2】已知等差数列
满足
,
.
(1)求
的通项公式;
(2)设等比数列
满足
.若
,求
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f28171b364c85b51806eddb2c210cc1e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a8532c10340004ea834b31d0fa0a5181.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)设等比数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eb4232bc49cf53920bb6132ce1fe158c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a53baab8bf6d53ca21de842db14d823.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f0a532e15e232cb4b99a8d4d07c89575.png)
您最近一年使用:0次
【推荐1】求和
(1)
;
(2)
,求
;
(3)
,求
.
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a3ed20aa6f12db8ee03f2ad7272c6052.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/675e3d98fd2d5ca6315ce8d3e0f041dd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/831ed34d8c6d99fdd0b94688ef03bfcb.png)
(3)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/479b3dd119b7494ff7aae733c100f837.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/da8fce33057796a3ce2c3930dffd0fb4.png)
您最近一年使用:0次
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(0.65)
名校
【推荐2】设等比数列
的前
项和为
,已知
,且
,
,
成等差数列.
(1)求数列
的通项公式;
(2)令
,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/039e4fe671d61e59b96ee525c9df43e8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/59b000a7c2c4f29d089bbd1445aa56d7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/59d3082535753c0bc409f739d99d5b68.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/207f8611762e9260b419fc95bed2e4b0.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
(2)令
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1ab67487086fb731b607dbda229b3caa.png)
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