解题方法
1 . 已知等差数列
,
为其前
项和,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54d6159f375a4812146c806e9fc5e1ec.png)
(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/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54d6159f375a4812146c806e9fc5e1ec.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e9096136726673d703f3defd1682f66d.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/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
您最近一年使用:0次
2020-11-24更新
|
347次组卷
|
5卷引用:2015届云南省弥勒市高三年级模拟测试一文科数学试卷
名校
解题方法
2 . 已知等差数列
的前
项和为
,且
,
,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/13f7b485c40a145a15755179ace757e1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/94339474cfe61111f152ef1636c8c5c8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7999465d0e871febde66296a0cbf058c.png)
A.-3 | B.-6 | C.3 | D.6 |
您最近一年使用:0次
2020-03-17更新
|
313次组卷
|
2卷引用:2019届云南省昆明市高考模拟考试(第四次统测)理科数学
解题方法
3 . 记数列
的前
项和为
为常数.下列选项正确的是( )
![](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/01a6994184f684e0a5dc9d8545348576.png)
A.若![]() ![]() | B.若![]() ![]() |
C.存在常数A、B,使数列![]() | D.对任意常数A、B,数列![]() |
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解题方法
4 . 已知
是公差为2的等差数列,
为
的前n项和,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/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ff9bc393eea6375f2e714f72d360197d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0382b4a2ab0657d2d6830bb6be2b17b6.png)
A.10 | B.12 | C.15 | D.16 |
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5 . 已知数列
是首项为正数的等差数列,数列
的前
项和为
.
(1)求数列
的通项公式;
(2)设
,求数列
的前20项和
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b40cdec22a05616d2464a4178759ec2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/17d95dcc91fc00fca9c00afc45b0837f.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/62e811da7ae7daeebf044014c51a58fc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5fce83115a50f99e08e9a2db7267aeed.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2f710b0e6ccca316852bf3a94f68135.png)
您最近一年使用:0次
名校
解题方法
6 . 在数列{an}中,a1=1,an+1=2n﹣an,则数列{an}的通项公式an=_____ .
您最近一年使用:0次
2020-04-30更新
|
253次组卷
|
6卷引用:2020届云南省曲靖市第一中学高三二模数学(文科)试题
2020届云南省曲靖市第一中学高三二模数学(文科)试题2020届云南省曲靖一中高三二模(理科)数学试题陕西省榆林市高新中学2019-2020学年高三上学期第一次月考数学(理)试题陕西省榆林市高新中学2019-2020学年高三上学期第一次月考数学(文)试题(已下线)文科数学-2020年高考押题预测卷03(新课标Ⅲ卷)《2020年高考押题预测卷》人教B版(2019) 选修第三册 一举夺魁 第五章 5.2.1 等差数列
名校
解题方法
7 . 已知等差数列
中,
,
.
(1)求
的通项公式;
(2)设
,求数列
的前
项和
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0f6116d8e7804e3cd438de153c55c10.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1b4fe3314f8b5f750c26cc375e071657.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/216876de04325fd250c38c485cbc34b7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5fce83115a50f99e08e9a2db7267aeed.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
您最近一年使用:0次
2018-04-05更新
|
1102次组卷
|
2卷引用:云南省昆明市2018届高三教学质量检查(二统)文科数学试题
解题方法
8 . 已知数列
满足:
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/047dbd9ff686703cad03aa383e5fec21.png)
________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49323b4c37902fb5f394e55ab63de6db.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/047dbd9ff686703cad03aa383e5fec21.png)
您最近一年使用:0次
2016-12-05更新
|
762次组卷
|
4卷引用:2017届云南昆明市高三上学期摸底统测数学(文)试卷
2010·上海徐汇·二模
9 . 设数列
是等差数列,且公差为
,若数列
中任意(不同)两项之和仍是该数列中的一项,则称该数列是“封闭数列”.
(1)若
,判断该数列是否为“封闭数列”,并说明理由?
(2)设
是数列
的前
项和,若公差
,试问:是否存在这样的“封闭数列”,使
;若存在,求
的通项公式,若不存在,说明理由;
(3)试问:数列
为“封闭数列”的充要条件是什么?给出你的结论并加以证明.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b71661efbd38645dd04a5c93ed6bc32c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5c02bc0c74292b1e8f395f90935d3174.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f069c238e1d9239fd3913b228965460f.png)
(2)设
![](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/50c81d6206a09006901987c51d7532cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d54d6777bfac3060e53da2ff964e5b26.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(3)试问:数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
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10 . 在等差数列
中,公差
,前5项和
,且
成等比数列.
(1)求数列
的通项公式;
(2)求
(
)的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/812be9806122241c476ba1db516c4823.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fca2cc2768794136c1e4da47d2f0873e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6143ff1743d17cc9c92f44dbcca18359.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c9a753110e0f5017675f12d779046480.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4cf5776ec7059c208daf01ca48a34915.png)
您最近一年使用:0次