名校
解题方法
1 . 随着智能手机的普及,手机计步软件迅速流行开来,这类软件能自动记载每个人每日健步的步数,从而为科学健身提供一定的帮助.某市工会为了解该市市民每日健步走的情况,从本市市民中随机抽取了2000名市民(其中不超过40岁的市民恰好有1000名),利用手机计步软件统计了他们某天健步的步数,并将样本数据分为
,
,
,
,
,
,
,
,
九组(单位:千步),将抽取的不超过40岁的市民的样本数据绘制成频率分布直方图如右,将40岁以上的市民的样本数据绘制成频数分布表如下,并利用该样本的频率分布估计总体的概率分布.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/23/a27d6f6b-06aa-43be-bd84-f08acc71679a.png?resizew=314)
(1)现规定,日健步步数不低于13000步的为“健步达人”,填写下面列联表,并根据列联表判断能否有
%的把握认为是否为“健步达人”与年龄有关;
(2)(ⅰ)利用样本平均数和中位数估计该市不超过40岁的市民日健步步数(单位:千步)的平均数和中位数;
(ⅱ)由频率分布直方图可以认为,不超过40岁的市民日健步步数
(单位:千步)近似地服从正态分布
,其中
近似为样本平均数
(每组数据取区间的中点值),
的值已求出约为
.现从该市不超过40岁的市民中随机抽取5人,记其中日健步步数
位于
的人数为
,求
的数学期望.
参考公式:
,其中
.
参考数据:
若
,则
,
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/97a5232c461d270a56a82dc9e5da934c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3b82da86d8dc7ffa62eaf5ef2afb17a6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/175028ab786d5b27a567a49b4925c4dc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/33275a5de8d697d79db3e547c42c7153.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ceef36065559d9dc75b327d31465d4da.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/29b9e3584324c4599be194e4c7b1dff3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6de13bf31535c9b9f87c0c3a004ef331.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab81a2e4f0ed0208946f705551e46d2e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/91fec24cba2105d020a5f4755ab2d3cb.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/23/a27d6f6b-06aa-43be-bd84-f08acc71679a.png?resizew=314)
分组 (单位:千步) | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() |
频数 | 10 | 20 | 20 | 30 | 400 | 200 | 200 | 100 | 20 |
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2b30b9e17c6e6f609dc4b6f6f8c7ecfa.png)
健步达人 | 非健步达人 | 总计 | |
40岁以上的市民 | |||
不超过40岁的市民 | |||
总计 |
(ⅱ)由频率分布直方图可以认为,不超过40岁的市民日健步步数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0d8b9ad2fcfff3dd546c5fdbedfe6238.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/29bcc248a7770a16fa10fc4602d71e0e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1100379a4385b9ce064847bc21760adc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c85481cd7e94130ef3aa05b4a39e79cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1c0ad7e7853a069537387b5192f73844.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/69e5a0f8dde758a4fafcfefd321d1d8b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0d8b9ad2fcfff3dd546c5fdbedfe6238.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf72e0630cfe5300667a2b95026abd5c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f022950e0faa45b617d497b01b5292b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f022950e0faa45b617d497b01b5292b9.png)
参考公式:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4e3821f70c08c5180e9b3086d3c9610f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/356b05e46b10ee51c3e43546d73ec96c.png)
参考数据:
![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() |
![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() |
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/34191455a1ff0f1592262f1cde5909ea.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eee8f3fc408e04bc80cc1e83b3b5d541.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/318d637d25ad8b394924e21507ee3768.png)
您最近一年使用:0次
2020-05-15更新
|
1102次组卷
|
4卷引用:2019届非凡联盟高三毕业班调研考试理数试题
2 . 已知函数
若方程
有且只有五个根,分别为
,
,
,
,
(设
),则下列命题正确的是_____________ (填写所有正确命题的序号).
①
;②存在k使得
,
,
,
,
成等差数列;
③当
时,
;④当
时,
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a696b23bf6556ef55eeeff5379080ba9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48dc6d0827a159050e3fa55164f258b7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c814128ea2139e33db94ea590e7c2223.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aec19b68e3add9d5bfcc6269a1855b87.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/291c25fc6a69d6d0ccfb8d839b9b4462.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/365b38a7689a8eede6820cd6f1fe952b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ee9b42973c53907f09f2de384c42fc5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4acd5e05f89802149b8b810c24d6ac73.png)
①
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b59d678b4c4aa0ec2bb04be1b2739a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c814128ea2139e33db94ea590e7c2223.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aec19b68e3add9d5bfcc6269a1855b87.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/291c25fc6a69d6d0ccfb8d839b9b4462.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/365b38a7689a8eede6820cd6f1fe952b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ee9b42973c53907f09f2de384c42fc5f.png)
③当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/44a4eaa80b44625890339d6a0065c241.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/779bc714193033c738599c30487bd42f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2f0d68648b10fce54dfc19c5ee60086d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1c12f6211f669ab04f4fe1c1b279ac2e.png)
您最近一年使用:0次
名校
3 . 已知
中,角
、
、
所对的边分别是
、
、
且
,
,有以下四个命题:
①
的面积的最大值为40;
②满足条件的
不可能是直角三角形;
③当
时,
的周长为15;
④当
时,若
为
的内心,则
的面积为
.
其中正确命题有__________ (填写出所有正确命题的番号).
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0faed94a64b2dcfc6801b4fca0f16675.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c94bb12cee76221e13f9ef955b0aab1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/071a7e733d466949ac935b4b8ee8d183.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f08ce80e91fdf435a8e3ec05be990e9d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5df6bb52902ef2cb7ba7ef1a681cdb1a.png)
①
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0faed94a64b2dcfc6801b4fca0f16675.png)
②满足条件的
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0faed94a64b2dcfc6801b4fca0f16675.png)
③当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c7b9446d7b31f0d6e044cf99deeb20aa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0faed94a64b2dcfc6801b4fca0f16675.png)
④当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c7b9446d7b31f0d6e044cf99deeb20aa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0faed94a64b2dcfc6801b4fca0f16675.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9fd2981bf2261343f905ec1b5355a3c4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/619096595112f0340a43b756e114dd3d.png)
其中正确命题有
您最近一年使用:0次
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|
1328次组卷
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4卷引用:安徽省合肥市第六中学2019-2020学年高一下学期开学考试数学试题
名校
4 . 若存在实常数k和b,使得函数
对其公共定义域上的任意实数x都满足:
恒成立,则称此直线
的“隔离直线”,已知函数
(e为自然对数的底数),有下列命题:
①
内单调递增;
②
之间存在“隔离直线”,且b的最小值为
;
③
之间存在“隔离直线”,且k的取值范围是
;
④
之间存在唯一的“隔离直线”
.
其中真命题的序号为__________ .(请填写正确命题的序号)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef655f5ecd8e5f7798c6e6747ba999b1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c34f5d4207fbf261bdbcf0926155230.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c17624c234559f04f5d94b7077f169a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/55adeff09c4d3d878785239f0bf2e27a.png)
①
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ffc247e5237219a6169648a3d20483c9.png)
②
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d39b814095580525ddc8176650af6b73.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3edbd40e04e2a943051fa83d6e511add.png)
③
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d39b814095580525ddc8176650af6b73.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c768cd9231a15caad0839f05d0f9207c.png)
④
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e8945c5bbc31c6617924d2c8aa29a091.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/17432e76b39908abe390d80f3c97f476.png)
其中真命题的序号为
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2018-09-02更新
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1123次组卷
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5卷引用:安徽省马鞍山市第二中学2018-2019学年高三上学期期中理科数学试题
名校
解题方法
5 . 如图,网格纸上小正方形的边长为1,粗线画出的是某三棱锥的三视图,则该三棱锥的外接球的半径为( )
![](https://img.xkw.com/dksih/QBM/2020/8/5/2521508738908160/2522583067230208/STEM/60d3cc13-b2db-418f-a2aa-7d593dc6a750.png?resizew=322)
![](https://img.xkw.com/dksih/QBM/2020/8/5/2521508738908160/2522583067230208/STEM/60d3cc13-b2db-418f-a2aa-7d593dc6a750.png?resizew=322)
A.![]() | B.![]() | C.11 | D.![]() |
您最近一年使用:0次
名校
解题方法
6 . 如图,网格纸上小正方形的边长为
,粗线画出的是某多面体的三视图,则该几何体的表面积为( )
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/2/ae7b6ffc-d2d2-485c-b765-3e5dac1091af.png?resizew=131)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdaa19de263700a15fcf213d64a8cd57.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/2/ae7b6ffc-d2d2-485c-b765-3e5dac1091af.png?resizew=131)
A.![]() | B.![]() |
C.![]() | D.![]() |
您最近一年使用:0次
2020-04-07更新
|
742次组卷
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2卷引用:安徽省六安市第一中学2019-2020学年高三下学期3月月考数学(理)试题
名校
7 . 黄金螺旋线又名鹦鹉螺曲线,是自然界最美的鬼斧神工.就是在一个黄金矩形(宽除以长约等于0.6的矩形)先以宽为边长做一个正方形,然后再在剩下的矩形里面再以其中的宽为边长做一个正方形,以此循环做下去,最后在所形成的每个正方形里面画出1/4圆,把圆弧线顺序连接,得到的这条弧线就是“黄金螺旋曲线了.著名的“蒙娜丽莎”便是符合这个比例,现把每一段黄金螺旋线与其每段所在的正方形所围成的扇形面积设为
,每扇形
的半径设为
满足
,若将
的每一项按照上图方法放进格子里,每一小格子的边长为1,记前
项所占的对应正方形格子的面积之和为
,则下列结论错误的是
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/67bfb31d3a254fee68fd4dbe986f6fa6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57ef6d44448092ebdb9e4a49d866a749.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0e8dc461847c60ee9cc8f476ec56c527.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a3062d705a57706d9321f42b8f64619d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57ef6d44448092ebdb9e4a49d866a749.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
A.![]() | B.![]() |
C.![]() | D.![]() |
您最近一年使用:0次
2019-10-12更新
|
1032次组卷
|
5卷引用:安徽省池州市第八中学2020-2021学年高三上学期12月月考理科数学试题
安徽省池州市第八中学2020-2021学年高三上学期12月月考理科数学试题山西省临汾市第一中学2018-2019学年高二下学期期末数学(理)试题(已下线)专题3.1 复杂数列的通项公式求解问题-玩转压轴题,进军满分之2021高考数学选择题填空题(已下线)专题10 数列(难点)-2020-2021学年高二数学下学期期末专项复习(北师大版2019选择性必修第一册、第二册)(已下线)【讲】专题9 与图表有关的数列问题
8 . 古希腊雅典学派算学家欧道克萨斯提出了“黄金分割”的理论,利用尺规作图可画出已知线段的黄金分割点,具体方法如下:取线段
,过点
作
的垂线,并用圆规在垂线上截取
,连接
;以
为圆心,
为半径画弧,交
于点
;以
为圆心,以
为半径画弧,交
于点![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7186b756542b54106635d9256528aa91.png)
,则点
即为线段
的黄金分割点.如图所示,在
中,扇形区域
记为Ⅰ,扇形区域
记为Ⅱ,其余部分记为Ⅲ.在整个图形中随机取一点,此点取自Ⅰ,Ⅱ,Ⅲ的概率分别记为
,
,
,(参考数据:
)则
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/5/dc468805-3b20-47c0-b093-ff344b779f3b.png?resizew=233)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0e7fa3aea72ccc36948a4a90f7368f71.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b79dd200766db27fb90d6bd1992cf658.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/78844aa08462f17c8f0a9ae28c231f67.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1a9c6a736e6eac98a676fa3232db5a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/764509115979e9958101808383672ec0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1a9c6a736e6eac98a676fa3232db5a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/88929f4ba0851730d5f941d426b87548.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b79dd200766db27fb90d6bd1992cf658.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7186b756542b54106635d9256528aa91.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b79dd200766db27fb90d6bd1992cf658.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/493139a1c94288bd86f90066527b63da.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a06b68dc88cc22301870ad2819a1a2c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5cd5f7bf025453ec103adfac05bbf665.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85d85d8c1f8add55bdc8c393be3ba2ae.png)
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9 . 如图,网格纸上小正方形的边长为
,粗实线及粗虚线画出的是某多面体的三视图,则该多面体的表面积为
![](https://img.xkw.com/dksih/QBM/2018/6/6/1961605516730368/1967039411896320/STEM/b276ac7eeeb94f3ca63f8cd73e64d062.png?resizew=152)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdaa19de263700a15fcf213d64a8cd57.png)
![](https://img.xkw.com/dksih/QBM/2018/6/6/1961605516730368/1967039411896320/STEM/b276ac7eeeb94f3ca63f8cd73e64d062.png?resizew=152)
A.![]() | B.![]() | C.![]() | D.![]() |
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2018-06-14更新
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2564次组卷
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5卷引用:安徽省铜陵市第一中学2019-2020学年高二上学期12月月考数学(理)试题
10 . 如图,网格纸上小正方形的边长为1,粗实线画出的是某几何体的三视图,则该几何体最长的棱长等于
![](https://img.xkw.com/dksih/QBM/2016/6/29/1572841445933056/1572841451978752/STEM/a2ba1239c97c47ed86812dabb4bba883.png)
![](https://img.xkw.com/dksih/QBM/2016/6/29/1572841445933056/1572841451978752/STEM/a2ba1239c97c47ed86812dabb4bba883.png)
A.6 | B.![]() | C.4 | D.8 |
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