1 . 设
是首项为
,公比为
的等比数列,
为数列
的前
项和.
(1)已知
,且
是
的等差中项,求数列
的通项公式;
(2)当
时,令
,求证:数列
是等差数列.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e72adb45c60c2f63b46e65ff787302bf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9aa8a716a31b0f51b70fdf9bdb257909.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/b6a24198bd04c29321ae5dc5a28fe421.png)
(1)已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c9b6e51986fe5d7a7265e0e93adcb4d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c1ccc6c74b8754e9bcbb3f39a11b6f1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/166862da64b2fcbfa63d7f474626dff9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6345f2b7885326cc3be5ff43ba38a367.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cc787eaf0db6cccd14acd421b4fa5ba0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
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2018-01-02更新
|
565次组卷
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4卷引用:【全国市级联考】陕西省宝鸡市2018届高三质量检测(三)数学(理)试题
【全国市级联考】陕西省宝鸡市2018届高三质量检测(三)数学(理)试题上海市十二校2018届高三联考数学试题(已下线)二轮复习测试专项 【新课标版理科数学】专题四 数列与不等式(已下线)二轮复习测试专项 【新课标版文科数学】专题四 数列与不等式
2013·北京西城·二模
名校
2 . 已知等比数列
的各项均为正数,
.
Ⅰ
求数列
的通项公式;
Ⅱ
设
证明:
为等差数列,并求
的前n项和
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fe229b24e2d56ff6b491725ceae4ff2f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad351b9fd1572a0bea733c69d6d4e9c2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11d71379442f28c038d367d49422cf90.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/987517758fad59f6f695761deb2a5ebd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fe229b24e2d56ff6b491725ceae4ff2f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11d71379442f28c038d367d49422cf90.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/987517758fad59f6f695761deb2a5ebd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fe2920ad541a6075bc4c0abb31b40691.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bee4464b3b4eb6e52ee02f095aae84f0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bee4464b3b4eb6e52ee02f095aae84f0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b708c8dcb2d66eb2ce0b3718a9cd924a.png)
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2018-08-31更新
|
1209次组卷
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12卷引用:2020届陕西省西安中学高三第一次模拟考试数学(文)试题
2020届陕西省西安中学高三第一次模拟考试数学(文)试题陕西省榆林市第十二中学2020-2021学年高三上学期12月第三次月考数学(文)试题(已下线)2013届北京市西城区高三二模文科数学试卷北京市第四中学2021届高三12月数学考试试题北京市第一七一中学2022届高三10月月考数学试题云南省宾川县第四高级中学2017-2018学年高一5月月考数学试题【全国百强校】江西省南昌市第十中学2017-2018学年高一5月月考试数学(文)试题重庆市南岸区2019-2020学年高一上学期期末数学试题江西省南昌八中、南昌二十三中等四校2018-2019学年高一下学期期中联考数学试题河南省开封市2020-2021学年高二上学期五县联考期中数学(理)试题黑龙江省双鸭山市友谊县高级中学2022-2023学年高二上学期期末考试数学试题黑龙江省克东县第一中学、克东县职业技术学校2022-2023学年高二下学期3月质量监测数学试题
解题方法
3 . 在等差数列
中,
,其前
项的和为
,若
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e472ad6e7bf7a6a409a43d4ea9035e0.png)
__________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d29d426508a27e51f5cc3fa47ffe4757.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1b98aaf753dadfe123692b929109e75c.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/77a6516938df4812f4135afa9da3a532.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e472ad6e7bf7a6a409a43d4ea9035e0.png)
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2017-04-18更新
|
1319次组卷
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2卷引用:2017届陕西省黄陵中学高三(重点班)4月月考(高考全国统一全真模拟二)数学(文)试卷
解题方法
4 . 在数列
中,
(
,
为常数),若平面上的三个不共线的非零向量
、
、
满足
,三点
、
、
共线且该直线不过
点,则
等于( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fd1a3fa35e426127e1a4a2528556942e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15a70b95c53fb6655721e2a8c61f5c2c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d60dcb171bb7fd972aab8294d63acdb3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f68628a408537b1cf3bf1ca2a69731b6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d20ec3efaa6b6ff5769e8999df5714a9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5297e510060a98fe2d25cb9a3561ca97.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/258cb9187f4d464ba98ccd9eff1b89fc.png)
A.![]() | B.![]() | C.![]() | D.![]() |
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真题
解题方法
5 . 已知等比数列
的公比为
.
(1)若
=
,求数列
的前n项和;
(2)证明:对任意
,
,
,
成等差数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6eb08ac8920645c616053c845978bdf1.png)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c1ccc6c74b8754e9bcbb3f39a11b6f1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d3ee48df4f41252ac48afeff1f4d7292.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)证明:对任意
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fd649176cce998793cf5cc256ec786c2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f255d0395fba51ca2d44293cca42e0a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20751aac59514228826454c21803e504.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/217b927efe12a98e1082ecd7f035b921.png)
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