1 . 已知等差数列
,满足
,
,正项数列
的前
项和为
,且
.
(1)求数列
和
的通项公式;
(2)求![](https://staticzujuan.xkw.com/quesimg/Upload/formula/64c445ae9b9b8e23fbafe3bf32cd58b8.png)
(3)在
,
之间插入1个数
,使
成等差数列,在
,
之间插入2个数
,
,使
成等差数列,
;在
,
之间插入
个数
,使
成等差数列.
①求
;
②求
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b065334d8f60c49f4bd3d9f1373fe4cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c83f24b32abf4b2cb15e326063e84a3d.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/5fc5eac09ed870c6711d94e558a25a9b.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
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/64c445ae9b9b8e23fbafe3bf32cd58b8.png)
(3)在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b715e7842b95f654f16056a7c7f2abe9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/13423c094861baf4b759b7f3d8c3c226.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a37711dd13e400346369d9d366018de7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/47e524013b85f8ecda29773f0fbcaf7e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/13423c094861baf4b759b7f3d8c3c226.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57483e04fd1840c87ac5325157149877.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/05ffd1d0d2f8ac94173a589eb526851c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bf922f855f5c6ba4f76ce9c72ab5465.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/50503e7c9b6e485253285cdd0c7df30b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/37e5531913e2f170465d8df01795cd51.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/686ece75006ad358f23314dc8a246e11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e95931effbd59c43e8ed1ea09962b84f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c12353dfeb825f6b593d46b94a24af2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/119dc692b6bb23baba1e27a909c4b6b2.png)
①求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0cc38dee83ec4bbaed6f62c55e59f4f4.png)
②求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/91ee33508bf5c846d5bd5c19d7b6844f.png)
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名校
2 . 公差大于零的等差数列
中,
,
,
成等比数列,若
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/715aaa320d35fd92b2dcd9573ab8b489.png)
_____________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f65fc200f10b97588a0c9896277c9c64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d33ec7236bccfedbe3baefd35e45f1e0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0e84c30444f13d37ada78285dc4f83b7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d1928c254cfada1f75a5cd1e34db5a63.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/715aaa320d35fd92b2dcd9573ab8b489.png)
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3 . 已知各项均为正数的数列
的前n项和为
,
,
,
,则
( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76aef4cdcb5af742ce28003b7b6c8c20.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/9edeb68b363f9771e9bc4d01a6cc7725.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09881de0dc186bbcd1e60eb00159ee97.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dc4e70b360f988fdbd92300ab22c4613.png)
A.511 | B.61 | C.41 | D.9 |
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4 . 已知数列
是等差数列,
,
,数列
的前n项和为
,且
,
(1)求数列
和
的通项公式;
(2)若集合
中恰有四个元素,求实数
的取值范围;
(3)设数列
满足
,
的前n项和为
,证明:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b61bd1c49c3310b78a3127ee668ec145.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bb8d5ef4302d8b46b28dda938d22500e.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/49e3a9bb248d5c1580b04a35bf884100.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
(2)若集合
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2b04a22b696271b8d4597d48a9838f07.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df64046e91b047037f19e4032e3b6de3.png)
(3)设数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57ef6d44448092ebdb9e4a49d866a749.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e145277adb96fc94f05367b50094b07e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57ef6d44448092ebdb9e4a49d866a749.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1f85c8d9210c7328fbe3d653ffede057.png)
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5 . 已知
为等差数列,前n项和为
,
是首项为2的等比数列,且公比大于0,
,
,
.
(1)求
和
的通项公式;
(2)若数列
满足:
,求数列
的前n项和
;
(3)若数列
满足:
,求
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/696d0e6b9013d2e5fdf3feb280c58e18.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7ff86be56090d576aad0c0945a6bd2bd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dbaed111f759d66a140168905f2026b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1fb0344eb6d3543a6c80803e85f60b26.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/b9221c0c92a526f65533cdc5400767af.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57ef6d44448092ebdb9e4a49d866a749.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
(3)若数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b783cf91e34e692ce8e171f0965cb53f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b0849999199ab6c92a157b0041d652b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/de97a62cdcd267dd753ec66f2adc3419.png)
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6 . 对于数列
,
,“
”是“数列
是等比数列”的( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a37a59558292ad6b3d0978bfd7484990.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/02ce9d5623b21817dd182b9058dc271a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
A.充分不必要条件 | B.必要不充分条件 |
C.充要条件 | D.既不充分也不必要条件 |
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7 . 已知等差数列
和
的前
项和分别为
,若
,则
( )
![](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/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/478421b81927e435cbcf5acafa89efd7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/39787fcb850d40db4372c2da58a83f18.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cfc016898072295c9975e552bd573f92.png)
A.![]() | B.![]() | C.![]() | D.![]() |
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解题方法
8 . 著名的“全错位排列”问题(也称“装错信封问题”是指“将n个不同的元素重新排成一行,每个元素都不在自己原来的位置上,求不同的排法总数.”,若将
个不同元素全错位排列的总数记为
,则数列
满足
,
.已知有7名同学坐成一排,现让他们重新坐,恰有两位同学坐到自己原来的位置,则不同的坐法有_________ 种
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96abfe2da27a63e6affb19a0c80236d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1bb750a274187cd3b78d078749f1fd4f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb06dc2843a7f13faa4450461ab58c42.png)
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名校
解题方法
9 . 已知数列
满足对任意的
,均有
,且
,
,数列
为等差数列,且满足
,
.
(1)求
,
的通项公式;
(2)设集合
,记
为集合
中的元素个数.
①设
,求
的前
项和
;
②求证:
,
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e145b6046bc80d0ffecc61ac67c87ca1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e6cbbec0f900da8864d00e396893c98.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/039e4fe671d61e59b96ee525c9df43e8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/18d8e8f821111de8075e5c3dfb22a5d6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/59dd6c97d2ee3e74ba5730f1cbcc1d43.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5e506112c35bdf08b18460d233eb6595.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
(2)设集合
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/87bc4ebb7c9c2323c75011db21226ae5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c59e7c7a84a4bdb959e95536d0404ceb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d3cfeacc29e6a61c5b3b4e439c0a91df.png)
①设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ffc96f796c19909fe80d0da1cd1d7823.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/960b682f983b053dc9064cf29c97e250.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2d51f9147b8265c0276c1f2c2659197.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b255b2aa8a99d13c0756a87906675c7f.png)
②求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d12d0bd9afdd4e53ff37f5bfcaa1106c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bac6b8de4384ff605892e8de5263de13.png)
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10 . 已知数列
为等差数列,
,
,数列
的前
项和为
,且
,
(1)求
的通项公式.
(2)已知
,求数列
的前
项和
.
(3)求证:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a0d29f34218cd60cc6e9ce4dcd13925.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d0876b7e2271371d8a7ea0e77a833a48.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/f57c3986996a5358b6d3b21e8889d1e8.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/62e567d7e9761951a266953c8d5042ac.png)
(2)已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bc869e9868c468b1989ffb6043d782f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57ef6d44448092ebdb9e4a49d866a749.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2d51f9147b8265c0276c1f2c2659197.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fbd85b79372dc6e596d465f738c3c300.png)
(3)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7036a7175fe91874f8320c61fc6207de.png)
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