1 . 已知数列
是等差数列,
是等比数列,且
,
,
,
.
(1)求
的通项公式:
(2)设
的前
项和为
,证明:
;
(3)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/627e48c5ab76f5d1874c57a40d32d89e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6abbd310bfce5fc6df04add486e95070.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/89fe0f4e8a80a2840c0f6929a8a6351b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/144958d8f106c2a5384404a612c35a31.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0441e285d990afd18061376145503267.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/1d0b808acfe2c8d5dbc280b5b83efc28.png)
(3)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac07953530e3c248b3438fb200fb1661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57ef6d44448092ebdb9e4a49d866a749.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
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2 . 已知等差数列
的前
项和为
,公差为
,且
,则下列说法正确的是( )
![](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/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5c02bc0c74292b1e8f395f90935d3174.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c4d57c747becc8ae70133a4ee6ff7721.png)
A.![]() | B.![]() |
C.当![]() ![]() | D.使![]() ![]() |
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解题方法
3 . 已知等差数列
的前9项和
,且
.若数列
满足![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4ac8b6f6e36d49dd53db30384497ef79.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/79c16a818ea61a1dc8aa68b4ca000e02.png)
(1)求数列
的通项公式;
(2)若数列
满足
,求数列
的前
项和
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/844f9e03483c710ad6cea8de4916fef6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/00d194ba78838168b0e2dd321063d807.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4ac8b6f6e36d49dd53db30384497ef79.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/79c16a818ea61a1dc8aa68b4ca000e02.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/62e567d7e9761951a266953c8d5042ac.png)
(2)若数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57ef6d44448092ebdb9e4a49d866a749.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b9221c0c92a526f65533cdc5400767af.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/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
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4 . 已知数列
满足
,则
( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c2c877b6511a2813a5eeacd0821be497.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/71dadecfaa30597a252f0c783962a881.png)
A.18 | B.19 | C.20 | D.21 |
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5 . 设等差数列
的前
项和为
,若
,则使
的最小正整数
的值是______ .
![](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/a32778285d8c6828e96827181733b34c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e9645bd4d2002993b90ec6d48f9c04f7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
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解题方法
6 . 各项均为正数的等比数列
的前n项和为
,且
,
,
成等差数列,若
,则
( )
![](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/cc79ce6a387dfe20817e5658b0b5af0c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/049cbc3e23ca095e9a542a3401066673.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c1ccc6c74b8754e9bcbb3f39a11b6f1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f966272f7781790ff27e40db6b525253.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9620357ea5be4037cfdccd09a27d3862.png)
A.15 | B.![]() | C.![]() | D.![]() |
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7 . 已知等差数列
的前
项和为
,
,
,则( )
![](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/1f02dfa42ca170196489e18a2a63addd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/97034664bd213a31e81b9625f83d0e26.png)
A.![]() | B.![]() ![]() |
C.使![]() ![]() | D.![]() |
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8 . 已知等差数列
的前n项和为
,且
,
.
(1)求数列
的第8项
及前20项和
;
(2)问数列
的前多少项和最小,最小值是多少?
![](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/88c37abf18ca94e006a0879e91a9a82b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/326c67df967048395f097e8b99bf29b5.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d7da2f386b78cdf6489efaa2f5820d3e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a27c112387e56c976489fa484c0d48f.png)
(2)问数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4dea1dd4ffcb4cf0697ca43079f6a1f2.png)
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9 . 已知
是等差数列,
,且
的前n项和为
,
,且
成等比数列,点
在
上.
(1)求
及
;
(2)判断是否存在正整数m、k使得
、
、
成等比数列.若存在,求出所有m、k的值;若不存在,请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c4ce64685821c3e55c07f151996ca8c3.png)
![](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/9186a380acea9af8b911de936123447d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7eb18614c7f1466ed722132f0d5e2da.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cd1257210e2e8ea21b053f0857d04444.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/999626ac9e7f3310b7f031953b93be45.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96abfe2da27a63e6affb19a0c80236d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
(2)判断是否存在正整数m、k使得
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/681ae1522a36768618f7ddaf74abbb7e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d22c854894d7a74582744df5e45d4c26.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/efae6cebf24728262ccd2df91904815d.png)
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10 . 等差数列
满足
,
,则
( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf97f3863a093129bd474f089839ff18.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6f3252a2abfd84c430084ae0e39a363e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/afd21f4cb498101d26b4aaa2e1a6addc.png)
A.2008 | B.2010 | C.2024 | D.2025 |
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