设等差数列
的前
项和为
,若
,则当
取最小值时,
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/1ff991e5e3c9bc608ab9463bee31dc6f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
A.6 | B.7 | C.6或7 | D.8 |
更新时间:2022-03-31 12:01:15
|
【知识点】 二次函数法求等差数列前n项和的最值
相似题推荐
单选题
|
较易
(0.85)
【推荐1】设等差数列
的前项和为
,若
,
,则当
取得最小值时,
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/a75739be7640de2ab1c3e191b9857a40.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c59b1a247775febe0106ba3898b9111e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
A.6 | B.6或7 | C.8或9 | D.9 |
您最近一年使用:0次
单选题
|
较易
(0.85)
解题方法
【推荐2】已知数列
中
,则数列
的前
项和
最大时,
的值为( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/93c4eb7860444c5b0780cd6203b96dfd.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/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
A.8 | B.7或8 | C.8或9 | D.9 |
您最近一年使用:0次