已知等差数列
的前
项和为
,若
,
,则
等于______ .
![](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/039e4fe671d61e59b96ee525c9df43e8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eb2c8dedfa4e56af166f7a3f6bd91ad2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2092f7f045371254f7d3a1e9a4d5befb.png)
更新时间:2023-03-17 23:35:12
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【推荐2】设
是等差数列,且
,
,则
的通项公式为___________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/039e4fe671d61e59b96ee525c9df43e8.png)
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解题方法
【推荐1】已知公差不为0的等差数列{an}的前n项和为Sn,若a3,a5,a10成等比数列,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/883c88e505916b697195068ec8158d44.png)
_________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/883c88e505916b697195068ec8158d44.png)
您最近一年使用:0次
填空题-单空题
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解题方法
【推荐2】记
为等差数列
的前n项和.已知
,
,则数列
的通项公式为![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e3f7fda69e2b32b9ced2239f915fa59b.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/c7abe2dbf91b745e81aa97bee35b0bda.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ea5cc09a66cb35ef1ee5fce4dd3da8ca.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e3f7fda69e2b32b9ced2239f915fa59b.png)
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