名校
1 . 已知
为等差数列,
为其前
项和.
.若
.则
的值为_________ .
![](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/36b98ef143f8159f3a7dafa1fd2f2370.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b11a355ae8682fb4cd7c922b9e2787f4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f3cf6f2bbe20a404fea41a4d2b1c4c7.png)
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2020-11-04更新
|
976次组卷
|
5卷引用:天津市滨海新区2020届高三居家专题讲座学习反馈检测数学试题(B卷)
天津市滨海新区2020届高三居家专题讲座学习反馈检测数学试题(B卷)天津市和平区2020-2021学年高三上学期期中数学试题(已下线)天津市耀华中学2020-2021学年高三上学期期中数学试题西藏日喀则市2021届高三学业水平考试数学(文)试题甘肃省白银市会宁县第四中学2020-2021学年高三上学期第三次月考数学(理)试题
名校
解题方法
2 . 等差数列
的公差为2,若
,
,
成等比数列,则数列
的前
项![](https://staticzujuan.xkw.com/quesimg/Upload/formula/04c2864e2ec3416cc4c081ac1f71a0af.png)
____________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e88093a749c0d46e0ee931ecfaff925.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/daf464629fa321a6ff7401ab79f07083.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d7da2f386b78cdf6489efaa2f5820d3e.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/04c2864e2ec3416cc4c081ac1f71a0af.png)
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2017-12-07更新
|
611次组卷
|
3卷引用:天津市实验中学2018届高三上学期第二次模拟数学(理)试题
名校
解题方法
3 . 已知公差不为0的等差数列{an}中,
依次成等比数列,则
=_________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/92a36b442f4a0800817325413caa325a.png)
![](https://img.xkw.com/dksih/QBM/2015/5/4/1572094650892288/1572094656847872/STEM/87b9f64018224e4eaf621b63bda6ca18.png?resizew=21)
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2016-12-03更新
|
1248次组卷
|
2卷引用:2015届天津市南开区高三一模文科数学试卷
2013·天津·一模
4 . 等差数列
的前
项和是
,若
,
,则
的值为______
![](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/856789e8ef3064cab89d8de2daf6069d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/118a07fcc90554cb842fba1c49956b98.png)
![](https://img.xkw.com/dksih/QBM/2013/7/17/1571283385417728/1571283390742528/STEM/acd1093a91834f6ab9f538e95ef1d254.png?resizew=23)
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