已知等差数列
中,若
,则
取最小值时的
( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6cb625cec7d0e9d1ce7d23c7dbe7a82.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f3cb8d72bb2e281b943b3b430138ef7.png)
A.9 | B.8 | C.7 | D.6 |
更新时间:2020-03-12 01:08:49
|
【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)
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,a1=2,且a1,a3,a4成等比数列,则Sn取最大值时n的值为( )
A.4 | B.5 | C.4或5 | D.5或6 |
您最近一年使用:0次
单选题
|
较易
(0.85)
名校
解题方法
【推荐2】已知等差数列
的前
项和为
,
,
,则
的最小值为( )
![](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/944234b576ca706f628f21ebe6535bd2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6978b1552e613c659cbb27dc423df1d0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
A.![]() | B.![]() | C.![]() | D.![]() |
您最近一年使用:0次