名校
1 . 若等差数列
的前n项和
有最大值,且
,那么
取正值时项数n的最大值为
![](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/fbfc09e305f5528f623a126506e770b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
A.15 | B.17 | C.19 | D.21 |
您最近一年使用:0次
2019-09-27更新
|
612次组卷
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2卷引用:山西省大同市2020届高三开学考试数学文科试题
2 . 已知等差数列
的前
项和为
.
(1)求数列
的通项公式;
(2)当
取得最小值时,求
的值.
![](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/7d2032b9469fc604e229eacabae10a5e.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
您最近一年使用:0次
2017-08-26更新
|
291次组卷
|
4卷引用:山西省孝义市2018届高三上学期入学摸底考试数学(文)试题