1 . “算两次”是一种重要的数学方法,也称做富比尼(G. Fubini)原理.“为了得到一个方程,我们必须把同一个量以两种不同的方法表示出来”(波利亚著《数学的发现》第一卷),即将一个量“算两次”.由等式
,
,
,利用“算两次”原理可得![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5602df7ab3fdae8cfc955b119fab781b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e361831759e890612594f2181a7be9f.png)
______ .(结果用组合数表示)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/17fe2dbab2e96245fce637484ceb7c3e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a37a59558292ad6b3d0978bfd7484990.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0704f453b2de48d36911f7db496bbf82.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5602df7ab3fdae8cfc955b119fab781b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e361831759e890612594f2181a7be9f.png)
您最近一年使用:0次
2024-05-30更新
|
366次组卷
|
3卷引用:河北省沧州市运东四校联考2023-2024学年高二下学期4月期中考试数学试题
2 . 已知某几何体的直观图如图所示,其中底面为长为4,宽为3的长方形.
(2)若该几何体的侧棱长均为
,求该几何体的侧面积S.
(2)若该几何体的侧棱长均为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/92aae6330e294aff063414cab40e1384.png)
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3 . 两个具有线性相关关系的变量的一组数据为
,
,
,
,则下列说法正确的是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2693f047cefe8477d055076b0fb25a03.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/590a7d430703d2d41a0171ff6a97dac5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/daa5e9bd516f6282483b92cfe6074623.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/28c66751ff7fe93ebc69986088141e8c.png)
A.若相关系数![]() |
B.相关系数r的值越小,成对样本数据的线性相关程度越弱 |
C.决定系数![]() |
D.决定系数![]() |
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4 . 根据3对数据
,
,
绘制的散点图知,样本点呈直线趋势,且线性回归方程为
,则
( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cffe17c304a7f157998c7fcf19283964.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c53cfa785f3d78e95a3b170180fd4b4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/062f492225dea1fad86164b7524bd5fb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c39de6f42237e6ce9cc9aa297c08c34.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a6c57bbef89a37f1a3808c0ceeac0c22.png)
A.10 | B.9 | C.8 | D.7 |
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5 . 已知复数z满足
,则
( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9fa4e27fd0278b5ea9bea87b9061abcc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b2d67321ace1e6b3be0fc0e5e8130022.png)
A.![]() | B.![]() | C.![]() | D.![]() |
您最近一年使用:0次
2024-05-24更新
|
457次组卷
|
3卷引用:河北省沧州市运东四校2023-2024学年高一下学期4月期中考试数学试题
河北省沧州市运东四校2023-2024学年高一下学期4月期中考试数学试题(已下线)模块五 专题2 全真基础模拟2(苏教版期中研习高一)内蒙古兴安盟乌兰浩特第一中学2023-2024学年高一下学期期中考试数学试题
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解题方法
6 . 已知
为椭圆
的两个焦点,
为椭圆
上一点,且
的周长为6,面积的最大值为
,则椭圆
的离心率为__________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4d2a97987f71835f519b462f5b8f5957.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f04443a0c1cf4808aea741c9f9379b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/33d776753746914c2410a3946c357f35.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7ffe8515ff6183c1c7775dc6f94bdb8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
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7 . 已知
是边长为4的正三角形,则
( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/01a9d11c1fdda8f3bb2ef921bc75f816.png)
A.8 | B.![]() | C.![]() | D.![]() |
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8 .
的内角
,
,
的对边分别为
,
,
,
.
(1)求角
的大小;
(2)若
,
的面积为
,求
的周长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.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/bdf7d9b37196f22db3b376bf13788580.png)
(1)求角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/850e2bc625eca71b12044de26db2fa3a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/18483c9c195ecd922772527fa85c0fcb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
您最近一年使用:0次
2024-05-16更新
|
1325次组卷
|
5卷引用:河北省沧州市沧衡学校联盟2023-2024学年高一下学期4月期中考试数学试题
解题方法
9 . 在
中,角A,B,C的对边分别为a,b,c,且
.
(1)求角A;
(2)若
的面积为1,求a的最小值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/44660cc086d5e3c8f03847da0f455f13.png)
(1)求角A;
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
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10 . 已知函数![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7275dc36161f2cb19a60b3fd3fa4817f.png)
(1)若函数
,证明:
在
上恒成立;
(2)若
,且
,证明:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7275dc36161f2cb19a60b3fd3fa4817f.png)
(1)若函数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6d40ef26f28c2b0ca3f71feccd30a32.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/098712632a6ebf8f223c1ed4ad4c8e5b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e5d6243e93c41978871cb23d8e66148d.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2472fe8ac5e5be36af547cab6eab4bbd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/733b867aa3a7966aa4eb6f55e2558979.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0c82098ddf6bcd9a5c93e1bbe8c9d69b.png)
您最近一年使用:0次