已知等差数列
的前n项和为
,
,
,则
最大时
( )
![](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/7dc352f71e67467a7a9d59bb1e0633db.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a515b81c98474b9e271d0ddf3d822331.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f3cb8d72bb2e281b943b3b430138ef7.png)
A.6 | B.5 | C.4 | D.3 |
2024·全国·模拟预测 查看更多[2]
更新时间:2024-01-08 11:19:34
|
相似题推荐
单选题
|
适中
(0.65)
名校
【推荐2】已知
为等差数列,
,则
的前9项和
( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3b0608fe1900d7bbae62cf82f2f6700b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dc4e70b360f988fdbd92300ab22c4613.png)
A.9 | B.17 | C.81 | D.120 |
您最近一年使用:0次
单选题
|
适中
(0.65)
名校
【推荐1】设
为公差小于零的等差数列,
为其前n项和,若
,则当n为何值时
最大
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/987517758fad59f6f695761deb2a5ebd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fe229b24e2d56ff6b491725ceae4ff2f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b708c8dcb2d66eb2ce0b3718a9cd924a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8cdb592f31681569045d482a0c161879.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b708c8dcb2d66eb2ce0b3718a9cd924a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11d71379442f28c038d367d49422cf90.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/987517758fad59f6f695761deb2a5ebd.png)
A.8 | B.9 | C.10 | D.12 |
您最近一年使用:0次
单选题
|
适中
(0.65)
名校
解题方法
【推荐2】设
为等差数列
的前n项和,且
,都有
,若
,则( )
![](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/0f8365233f341451598eb50525a1557a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e5349aa8be919c7a1ceae1cdc00d3e54.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76788e7a7d1a21e80ad5e124621b2a3e.png)
A.![]() ![]() | B.![]() ![]() |
C.![]() ![]() | D.![]() ![]() |
您最近一年使用:0次