名校
1 . 已知数列
,
都是公差为1的等差数列,
是正整数,若
,则
( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fe229b24e2d56ff6b491725ceae4ff2f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bee4464b3b4eb6e52ee02f095aae84f0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36f572b99ec09f2c6cbf9ea12ed4cdd2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8445417ae1e67df7587b0f5e8ebdda6b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/44e8556df2e52f6c7794ec976fc90b18.png)
A.81 | B.99 | C.108 | D.117 |
您最近一年使用:0次
2016-01-13更新
|
326次组卷
|
2卷引用:河北省大名县第一中学2018届高三(实验班)上学期第一次月考数学(文)试题
2 . 已知数列
则
是该数列的
![](https://img.xkw.com/dksih/QBM/2016/1/12/1572428548292608/1572428553723904/STEM/65c8b7b752b542efb186f2ab46715d01.png)
![](https://img.xkw.com/dksih/QBM/2016/1/12/1572428548292608/1572428553723904/STEM/6edf6e4da77e41f39c3f7884ed26732b.png)
A.第16项 | B.第17项 | C.第18项 | D.第19项 |
您最近一年使用:0次
3 . 已知等差数列
中,前10项的和等于前5项的和.若
则
( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4be2164a2c67d6163faee87a10942bb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6f1a487bae5d328ef9ce3632c9f73d0c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a6c57bbef89a37f1a3808c0ceeac0c22.png)
A.10 | B.9 | C.8 | D.2 |
您最近一年使用:0次
2010·河北邯郸·二模
名校
4 . 设
为等差数列,
为其前
项和,且
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/adf14ebc775db2414a5a960badca8960.png)
![](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/30a1097dc7b15dadf3bacc1f28cb048d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/adf14ebc775db2414a5a960badca8960.png)
A.![]() | B.![]() | C.![]() | D.![]() |
您最近一年使用:0次
5 . 设数列
是以3为首项,1为公差的等差数列,
是以1为首项,2为公比的等比数列,则
=
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d737c1047a14cee12a6671383e244fa5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a89d1f32c1605cfdb8e8855051b9f6ec.png)
![](https://img.xkw.com/dksih/QBM/2016/1/8/1572425959448576/1572425965150208/STEM/52cad56cabd14895be6377e40fe98594.png)
A.15 | B.72 | C.63 | D.60 |
您最近一年使用:0次
2016-12-03更新
|
643次组卷
|
3卷引用:2015-2016学年河北省成安一中、永年二中高二上期中理科数学试卷
6 . 已知等差数列
的前n项和为
等于
![](https://img.xkw.com/dksih/QBM/2016/5/5/1572618199646208/1572618205429760/STEM/7b9e9643d4b3451d8639b12aaf3c555c.png)
![](https://img.xkw.com/dksih/QBM/2016/5/5/1572618199646208/1572618205429760/STEM/8a145c1d69b646f3b65a79a3ddd23b01.png)
A.-90 | B.-27 | C.-25 | D.0 |
您最近一年使用:0次
2016-12-02更新
|
819次组卷
|
3卷引用:2015-2016学年河北省成安县一中高二1月月考文科数学试卷
7 . 已知
为等比数列
的前
项和,且
,则
等于
![](https://img.xkw.com/dksih/QBM/2016/12/27/1619411074736128/1619411074932736/STEM/0597f84e84ae40fdaa21e15c3e0bf02d.png)
![](https://img.xkw.com/dksih/QBM/2016/12/27/1619411074736128/1619411074932736/STEM/8a59f22aa85144ff9b6675104af17834.png)
![](https://img.xkw.com/dksih/QBM/2016/12/27/1619411074736128/1619411074932736/STEM/954b0eb40fce4a068e15094aa3fa2108.png)
![](https://img.xkw.com/dksih/QBM/2016/12/27/1619411074736128/1619411074932736/STEM/7304197a5ec7475b842873bd093c145b.png)
![](https://img.xkw.com/dksih/QBM/2016/12/27/1619411074736128/1619411074932736/STEM/b8d26cdb51e44cf0a613031356afad97.png)
A.![]() | B.![]() |
C.![]() | D.![]() |
您最近一年使用:0次
12-13高三上·湖北黄冈·阶段练习
8 . 一同学在电脑中打出如下若干个圆:○●○○●○○○●○○○○●○○○○○●…,若依此规律继续下去,得到一系列的圆,则在前2 012个圆中共有●的个数是
A.61 | B.62 | C.63 | D.64 |
您最近一年使用:0次
9 . 已知数列-1,
,
,-4成等差数列,-1,b1,b2,b3,-4成等比数列,则
的值为
![](https://img.xkw.com/dksih/QBM/2016/1/21/1572456083283968/1572456089067520/STEM/70af9058ca724840a62088f921de4473.png)
![](https://img.xkw.com/dksih/QBM/2016/1/21/1572456083283968/1572456089067520/STEM/c0e79cbaf5664a738b00f4fc23f2ed15.png)
![](https://img.xkw.com/dksih/QBM/2016/1/21/1572456083283968/1572456089067520/STEM/34ad156d5f3b4be48bbce5c6f1540114.png)
A.![]() | B.-![]() | C.![]() ![]() | D.![]() |
您最近一年使用:0次
10 . 已知
为等比数列
的前
项和,且
,则
等于
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4be2164a2c67d6163faee87a10942bb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a43a065980cc42bb10ee34953aa2f4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7fc11a860719719f43ec5c2179902946.png)
A.![]() | B.![]() |
C.![]() | D.![]() |
您最近一年使用:0次
2017-02-08更新
|
367次组卷
|
2卷引用:2017届河北磁县一中高三11月月考数学(文)试卷