已知等差数列
中,
,
为数列
的前
项和,则
( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e40d322235f8346a96eecdbfd2f8d2a6.png)
![](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/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/adf14ebc775db2414a5a960badca8960.png)
A.30 | B.35 | C.40 | D.45 |
2020·河北·模拟预测 查看更多[2]
更新时间:2021-06-23 09:39:47
|
相似题推荐
单选题
|
较易
(0.85)
名校
【推荐2】已知
为正项等比数列,
为等差数列,且
,则下列关系式必成立的是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4be2164a2c67d6163faee87a10942bb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/43b7e7cd571c8cd141cbbfe5d0890bf6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e89503358baa149f90c929b55dc2cec3.png)
A.![]() | B.![]() |
C.![]() | D.![]() |
您最近一年使用:0次
单选题
|
较易
(0.85)
名校
【推荐1】等差数列
的前n项和记为
.若
为一个确定的常数,则下列各数也是常数的是.
![](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/495776b7cc57c372eb4d60a3fb5cfd3b.png)
A.![]() | B.![]() | C.![]() | D.![]() |
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】在前
项和为
的等差数列
中,
,
,则
( )
![](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/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bb0ea3ca5891318d12aacd55c8e59cfb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8c12588db47476f2cf7e18b929ed9e39.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/614306cc3f34bdee4d5d885b79667645.png)
A.3 | B.10 | C.15 | D.25 |
您最近一年使用:0次