1 . 若当且仅当
时,等差数列
的前
项和
取得最大值,则数列
的通项公式可以是________ .(写出满足题意的一个通项公式即可)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08ec5d76db9bd05547932966c9913dc2.png)
![](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/63d471926f7b27322d90c82b9ce21d3d.png)
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解题方法
2 . 已知等差数列
的前
项和为
,且![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4681d28548b554e3413ad5977c9a20e9.png)
(1)求
的通项公式;
(2)求数列
的前20项和
;
(3)在数列
中是否存在不同的两项,使得它们的等比中项中至少有一个仍是该数列中的项?若存在,请写出这两项的值(写出一组即可);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/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4681d28548b554e3413ad5977c9a20e9.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b91adba8efbf964e9e35547b0fd0ea36.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2f710b0e6ccca316852bf3a94f68135.png)
(3)在数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
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3 . 记
为等差数列
的前
项和,若
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd707b69a11f8de5566f23c1a2a9ff5a.png)
___________ ,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/050294162a78c6f4d6a87849bd3049a3.png)
___________ .(写出符合要求的一组答案即可)
![](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/fe98e779c871f57b79275a417a6d0b6a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd707b69a11f8de5566f23c1a2a9ff5a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/050294162a78c6f4d6a87849bd3049a3.png)
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4 . 命题“数列的前
项和
”成立的充要条件是________ .(填一组符合题意的充要条件即可,所填答案中不得含有字母
)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/550dc616e1c78abce72f57b48c3e6238.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
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名校
解题方法
5 . 已知数列
各项均为正数,
,
,且
对任意
恒成立.
(1)若
,求
的值;
(2)若
,①证明:数列
是等差数列;②在数列
中,若
,
,
构成等比数列求符合条件的一组
的值(满足题意的一组值即可),说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4be2164a2c67d6163faee87a10942bb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b065334d8f60c49f4bd3d9f1373fe4cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2693734765399876e9e93cdb110231c4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2f4ed0ce50dc28088ad348932a998e3a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cea4ac187cbb465180e89f38250b3970.png)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e8c45e4c4ab30665338dd87a2258f23.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f65fc200f10b97588a0c9896277c9c64.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a8a0eecb5b800fce9ae10aed86ffee62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4be2164a2c67d6163faee87a10942bb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4be2164a2c67d6163faee87a10942bb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e88093a749c0d46e0ee931ecfaff925.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/681ae1522a36768618f7ddaf74abbb7e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a9cb6b19b630ece366d3288724a660b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/865f61c8bbe153f7010bcc28a9ebf462.png)
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6 . 已知常数a≠0,数列
的前n项和为
,且![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a1845e897e09f7504a36ca6b5adcc0b4.png)
(1)求证:数列
为等差数列;
(2)若
且数列
是单调递增数列,求实数a的取值范围;
(3)若
数列
满足:
对于任意给定的正整数k,是否存在p,
,使
若存在,求p,q的值(只要写出一组即可);若不存在,说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a4af60e70f570ec61b8170214977bc3c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a1845e897e09f7504a36ca6b5adcc0b4.png)
(1)求证:数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6678c59e26c0bea46f44e1aeb3d15422.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5fce83115a50f99e08e9a2db7267aeed.png)
(3)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c45051c4c45caa2bf4763206d5708bd7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/38ef4c4439b36c2847b0056a116d56d4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3849d50adf105c12964bafa7b359aabb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d21cfd1ad0f4254be1d88c6577b6bbb2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d383728b0f29a81482776d888e631f62.png)
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名校
7 . 数列
满足
,
,实数
为常数,①数列
有可能为常数列;②
时,数列
为等差数列;③若
,则
;④
时,数列
递减;则以上判断正确的有______ (填写序号即可)
![](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/fedcf01e8f41a2610d182c32538a3ada.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f0a532e15e232cb4b99a8d4d07c89575.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5095a28bb1b91bf6bed9e2cfbd76bb18.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/41cf1da18d91f7c98086553d157d1a87.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/29e25fd655fccad3f351a4a59a4ac7b1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d69fa853794ba03bf379140ecccf59c9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2f0d68648b10fce54dfc19c5ee60086d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
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2020-05-25更新
|
486次组卷
|
3卷引用:2020届湖北省荆州市沙市中学高三下学期5月第三次模拟数学(理)试题
解题方法
8 . 已知数列
是公差为正数的等差数列,数列
为等比数列,且
,
,
.
(1)求数列
、
的通项公式;
(2)设数列
是由所有
的项,且
的项组成的数列,且原项数先后顺序保持不变,求数列
的前2019项的和
;
(3)对任意给定的
是否存在
使
成等差数列?若存在,用
分别表示
和
(只要写出一组即可);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/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/654185eecdb28389c7994e5187671be4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccfe26b3ab1cd6a93075f24b696b0cef.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/144958d8f106c2a5384404a612c35a31.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
(2)设数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57ef6d44448092ebdb9e4a49d866a749.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce829c29eebf57ddc93f9127cdb1f37c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57ef6d44448092ebdb9e4a49d866a749.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1adb2d553c2fa56337284d5c62adccba.png)
(3)对任意给定的
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7b3743297adc123fd45565bd52ff240c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6b9f65fe4c86d340d9da60c167b3256e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73a135ced51bfd0299c44abe4a6546ba.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f0a532e15e232cb4b99a8d4d07c89575.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1010846eeec6c9da29640f5aa3f8738.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11bc05f41215f9894e11d1df0465751a.png)
您最近一年使用:0次
名校
解题方法
9 . 已知常数
数列
的前
项和为
,
且![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ea73a8c287424d6281822f8a340106e6.png)
(1)求数列
的通项公式;
(2)若
且数列
是单调递增数列,求实数
的取值范围;
(3)若
数列
满足:
对于任意给定的正整数
,是否存在
使
?若存在,求
的值(只要写出一组即可);若不存在,说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f01592e40f9c9db0bf3cceb585a2b9dd.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/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b065334d8f60c49f4bd3d9f1373fe4cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ea73a8c287424d6281822f8a340106e6.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6678c59e26c0bea46f44e1aeb3d15422.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
(3)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c45051c4c45caa2bf4763206d5708bd7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57ef6d44448092ebdb9e4a49d866a749.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8881be0063af5f5008a97ff17a4681da.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f0a532e15e232cb4b99a8d4d07c89575.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a5dde3668a8dcc447724aa738bdbdbd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0e62f7e42856aa40f3b1a1d8890762cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0cd5371a6f0f82c65dd22f75f8b807c1.png)
您最近一年使用:0次
11-12高三上·江苏·阶段练习
名校
10 . 已知常数
,数列
的前
项和为
,
且
.
(1)求证:数列
为等差数列;
(2)若
,且数列
是单调递增数列,求实数
的取值范围;
(3)若
,数列
满足:
对于任意给定的正整数
,是否存在
,使
?若存在,求
的值(只要写出一组即可);若不存在,说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20849c00c47cbdc43f18d53341b6c4e5.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/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b065334d8f60c49f4bd3d9f1373fe4cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ea73a8c287424d6281822f8a340106e6.png)
(1)求证:数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60e8f700816151c538d07e6bc7532550.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
(3)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/200f24e682c93e02a87f3f9d57dc5d40.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57ef6d44448092ebdb9e4a49d866a749.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8881be0063af5f5008a97ff17a4681da.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f0a532e15e232cb4b99a8d4d07c89575.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f11539515797827d90a6c9f161d82346.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0e62f7e42856aa40f3b1a1d8890762cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0cd5371a6f0f82c65dd22f75f8b807c1.png)
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