已知数列
为等差数列,
为其前
项和,
,则
( )
![](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/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/016e5f50e94ae9c5ff1fb90355d85eeb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eb261bb45b5137a7236ccddcfdface6f.png)
A.7 | B.14 | C.28 | D.84 |
更新时间:2020-04-14 02:10:09
|
相似题推荐
单选题
|
适中
(0.65)
名校
【推荐1】等差数列
中,设前
项和为
,
,则
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/5733e47b25c81541ddd18dc39c42904a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ba48780e63a87aaf7f1d7fa29dd56b5c.png)
A.80 | B.85 | C.90 | D.95 |
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】若
成等比数列,
是
的等差中项,
是
的等差中项,则
( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76f0649064a085fb74c997fb507a9b6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/632244ea6931507f8656e1cc3437d392.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c9a475fec8ded321e10a6697319fb975.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2ce603776cb1963a38a23949026e8d1a.png)
A.4 | B.3 | C.2 | D.1 |
您最近一年使用:0次
单选题
|
适中
(0.65)
解题方法
【推荐1】在
中,
,点O满足
,
,数列
中,
,则
( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/79ace47cc6398b1101cf428095e8a378.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/242b14a89363fa1e1a3b74ed989a5311.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0e86fdb0f93bc3d14100b5540b6ddab2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/44bc66f13763be9aa6a07585bffd8b1f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e3f7fda69e2b32b9ced2239f915fa59b.png)
A.![]() | B.![]() | C.![]() | D.![]() |
您最近一年使用:0次
单选题
|
适中
(0.65)
【推荐2】已知正项数列
的前
项和为
,满足
,则
( )
![](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/e48ab52062426760d1a916e8be81e049.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ee8a06afd3e1d32d5af37005e50f869c.png)
A.![]() | B.![]() | C.![]() | D.![]() |
您最近一年使用:0次