名校
解题方法
1 . 设
为数列
的前
项和,
,则“
”是“数列
是以
为公比的等比数列”的( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](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/36f7cf472cbb97be7f308ea4f9eab5de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/129cdeea82367ac15a49f71d62c1dd63.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9aa8a716a31b0f51b70fdf9bdb257909.png)
A.充要条件 | B.充分不必要条件 |
C.必要不充分条件 | D.既不充分也不必要条件 |
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2 . 定义:在一个有穷数列的每相邻两项之间插入这两项的和,形成新的数列,我们把这样的操作称为该数列的一次“和扩充”,例如:数列
经过第一次“和扩充”后得到数列
;第二次“和扩充”后得到数列
.设数列
经过
次“和扩充”后得到的数列的项数为
,所有项的和为
.
(1)若
,求
;
(2)求不等式
的解集;
(3)是否存在数列
,使得数列
为等比数列?请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/680e9ef551b325387ab31dca1f893705.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aa2d5ffc86bda25b7fd377267ae3e7df.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef1d5a07307b7d2603995105ab2490f9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76f0649064a085fb74c997fb507a9b6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bf83e20035c3afd6d26ebfd53d768a70.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f33d09c34e89bc99fbeb30bac80d4f90.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3a642ed9870f81d906816bc0db3d621c.png)
(2)求不等式
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4dcd08431daac10be93e6fafbc5d4a90.png)
(3)是否存在数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/863d3bc9596595b16499a46479526680.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/846fa57d92d6ad44d6a0cafad1e71ed4.png)
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3 . 已知数列
的前
项和为
,且满足
.
(1)求证:数列
为等比数列;
(2)已知
,求数列
的前
项和.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76aef4cdcb5af742ce28003b7b6c8c20.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/0df387df5d97ffab16c92b6f6c0f7728.png)
(1)求证:数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/82f8b6edfb7d680d88ed991d5c552c43.png)
(2)已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d1e8a0503abebc7b0f2a60b2ec15d282.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f329b217e1051b23f0d61023cdc6e69.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
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名校
4 . 已知
为等差数列,
是公比为2的等比数列,且
,求集合
中元素个数__________ .
![](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/9577321bd85f232a0fecb06639171e90.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/db84e10c0bfea0a3357785f7cfc9a2b2.png)
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5 . 已知等差数列
中,
成等比数列,
.
(1)求数列
的通项公式;
(2)令
,记数列
的前n项和为
,求
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fe05476226ca5e715958ca7d43cd1aa5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a94d034e1bfd87075162d40b2f81d1ab.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)令
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/216876de04325fd250c38c485cbc34b7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a34a901aa78366ac960f5f4e7f1fcbac.png)
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名校
解题方法
6 . 已知等比数列
满足
,
,则其前
项和![](https://staticzujuan.xkw.com/quesimg/Upload/formula/04c2864e2ec3416cc4c081ac1f71a0af.png)
___________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/92e9d3644920a6654c41de61b7f3636d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/51edb7027369b194443909607470afec.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/04c2864e2ec3416cc4c081ac1f71a0af.png)
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7 . 若数列
的前
项和为
,关于正整数
的方程
记为
,命题
:对于任意的
,存在等差数列
使得
有解;命题
:对于任意的
,存在等比数列
使得
有解;则下列说法中正确的是( )
![](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/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/159f08aed9d004e3194fb892d49c9f58.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1010846eeec6c9da29640f5aa3f8738.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/10bbdef421c976962a270a2beabbad91.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9aa8a716a31b0f51b70fdf9bdb257909.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/10bbdef421c976962a270a2beabbad91.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
A.命题![]() ![]() | B.命题![]() ![]() |
C.命题![]() ![]() | D.命题![]() ![]() |
您最近一年使用:0次
名校
解题方法
8 . 已知数列
的前
项和为
,下列说法正确的是( )
![](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/696d0e6b9013d2e5fdf3feb280c58e18.png)
A.若![]() ![]() ![]() ![]() |
B.若![]() ![]() ![]() ![]() |
C.若![]() ![]() |
D.若![]() ![]() |
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9 . 已知数列
是公比为2的等比数列,数列
是等差数列,
,
,
.
(1)求数列
,
的通项公式;
(2)设
,求数列
的前
项和
.
![](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/4ed1b0d16948c3afaa12adf30e839151.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/65a4446af2614adaa44589dfcb8de156.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fffc1532361e0dcbd663ef8a8faf08c1.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1d44ddab6e0c60119be69985ae7fa65b.png)
![](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/08eb71ecf8d733b6932f4680874dbbf3.png)
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10 . 已知数列
中,
,则
于( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a3bad85fca280cee855545e84fba867b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5da4cd81500bdb43118150dbdb1541e6.png)
A.![]() | B.![]() | C.![]() | D.![]() |
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