名校
1 . 等差数列
的前n项和为
,若
,则
=_________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/71d3b0e726285caa07f54bb52ab59c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c1d3c0e668468adc3108c788cf701b9.png)
您最近一年使用:0次
2020-11-16更新
|
500次组卷
|
3卷引用:宁夏大学附属中学2020-2021学年高二上学期期中考试数学(理)试题