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1 . 若7个正数成等差数列,且这7个数的和为5,则此等差数列的公差
可能是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5c02bc0c74292b1e8f395f90935d3174.png)
A.![]() | B.![]() | C.![]() | D.![]() |
您最近一年使用:0次
2 . 差分法的定义:若数列
的前
项和为
,且
,则
时,
.例如:已知数列
的通项公式是
,前
项和为
,因为
,所以
.
(1)若数列
的通项公式是
,求
的前
项和
;
(2)若
,且数列
的前
项和分别为
,证明:
.
![](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/314fa1f4da470780673cc7246974180c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0704f453b2de48d36911f7db496bbf82.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9361afc7cc02253140585eedc39a695d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/677e46ecd051c92489c0d1d458932f37.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/e3bd2e55bb083a90ecba8cc98fac9536.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/237ce153a42d4e2378d5435051734cb3.png)
(1)若数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8bd845d1bfac72200926447db04563fc.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/08eb71ecf8d733b6932f4680874dbbf3.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/77af844c4444e536adae9bc0b1cff614.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c04f062dc12653209868713f2142fe06.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ee1c51f15c934050099b460b19a04f4b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/038e3af7c9f2fb642b9209415662aeff.png)
您最近一年使用:0次
2024-05-30更新
|
166次组卷
|
2卷引用:黑龙江省伊春市铁力市第一中学校2023-2024学年高二下学期期中考试数学试卷
3 . 某人通过计步仪器,记录了自己100天每天走的步数(单位:千步)得到频率分布表,如图所示
![](https://img.xkw.com/dksih/QBM/editorImg/2022/6/29/4620aea1-d9c4-48cd-ba77-66d79d7d31b2.png?resizew=210)
(1)求频率分布表中
的值,并补全频率分布直方图;
(2)估计此人每天步数不少于1万步的概率.
分组 | 频数 | 频率 |
[4,6) | 5 | 0.05 |
[6,8) | 15 | 0.15 |
[8,10) | 20 | 0.20 |
[10,12) | ![]() | ![]() |
[12,14) | 20 | 0.20 |
[14,16] | 10 | 0.10 |
合计 | 100 | 1 |
![](https://img.xkw.com/dksih/QBM/editorImg/2022/6/29/4620aea1-d9c4-48cd-ba77-66d79d7d31b2.png?resizew=210)
(1)求频率分布表中
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/632244ea6931507f8656e1cc3437d392.png)
(2)估计此人每天步数不少于1万步的概率.
您最近一年使用:0次
2022-06-27更新
|
795次组卷
|
4卷引用:黑龙江省伊春市铁力市马永顺中学2022-2023学年高二上学期期末数学试题
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4 . 函数零点的涵义是( )
A.一个点 | B.函数图象与![]() |
C.函数图象与![]() | D.函数图象与![]() |
您最近一年使用:0次
2023-02-05更新
|
329次组卷
|
2卷引用:2024年黑龙江普通高中学业水平合格性考试数学仿真模拟试卷1