1 . 如图,三棱柱满足棱长都相等,且
平面
,
是棱
的中点,
是棱
上的动点,设
,随着
增大,平面
与底面
所成钝二面角的平面角是( )
A.减小 | B.先减小再增大 | C.先增大再减小 | D.增大 |
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6338ae12ba6f51cd6e495b31fdea9c57.png)
(1)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6b108ab31cc093f03cf48ad65429889e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/280af9729db36b69a0a071edcbfb5f1d.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/94440d3e4c073f94f2b266ff99d50e74.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/942c2141d01bde6b48210c56a17fc75e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1938c093dd2fbcb752d0eb7a18d143b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
(3)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e51a4785e5372dc6b88ec3b5a31a1de3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d562dc22dfb3b81d0c3f88b54d063c2f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
不患肺癌 | 患肺癌 | 合计 | |
不吸烟 | 24 | 6 | 30 |
吸烟 | 6 | 14 | 20 |
合计 | 30 | 20 | 50 |
A.可以通过计算![]() ![]() ![]() |
B.可以通过计算![]() ![]() |
C.可以通过计算![]() ![]() ![]() |
D.可以通过计算![]() ![]() |
(1)若数列
![](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/0f30f56664446f32dbbc2c5f12a99374.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1b0ed9533c1ea30a87249539a005e62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e48e167c9bcef9eb89d7a456d8ca21b7.png)
(2)数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7476db4d8d32edf309372a3ef067b839.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ec25b9d7ca47b780a744c2ebbf31d925.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4f6b18b109a656b62fb173680ae99ca7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4004a42ff7dc0afb6d53c73859e7c49b.png)
(3)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c4f5908d6a1217e493ed7586b6964dd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3420606c96b68fb884c839923fd20a25.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f5971b06a0758bb830c4e09a25bb665a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/37fb370b8bd5422314299f1dd4f1ec25.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e976c0663fa749ca749f99842d21ca03.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1c4cdcb32e3a0ce527c13978c022a54.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0e4b0cd80d95662729de6af4fa5add73.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3440756e96122c23a882a4592b45b4f2.png)
A.0 | B.1 | C.2 | D.3 |
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/699f18e45e11545da4cb546bcc1b5587.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a95d833378fedd8a5eb2135c54f3642e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
6 . 某校举行“强基计划”数学核心素养测评,要求以班级为单位参赛,最终高三一班(45人)和高三二班(30人)进入决赛.决赛规则如下:现有甲、乙两个纸箱,甲箱中有4个选择题和2个填空题,乙箱中有3个选择题和3个填空题,决赛由两个环节组成,环节一:要求两班级每位同学在甲或乙两个纸箱中随机抽取两题作答,作答后放回原箱,并分别统计两班级学生测评成绩的相关数据;环节二:由一班班长王刚和二班班长李明进行比赛,并分别统计两人的测评成绩的相关数据,两个环节按照相关比赛规则分别累计得分,以累计得分的高低决定班级的名次.
(1)环节一结束后,按照分层抽样的方法从两个班级抽取20名同学,并统计每位同学答对题目的数量,统计数据为:一班抽取同学答对题目的平均数为1,方差为1;二班抽取同学答对题目的平均数为1.5,方差为0.25,求这20人答对题目的均值与方差;
(2)环节二,王刚先从甲箱中依次抽出两道题目,答题结束后将所答题目放入乙箱,然后李明在乙箱中再依次抽取两道题目,求李明抽取的两题均为选择题的概率.
7 . 已知,集合
,若集合A恰有8个子集,则n的可能值的集合为
8 . 设函数的定义域为
,满足
,当
时,
,则
9 . 若抛物线的焦点到它的准线距离为1,则实数m=
10 . 已知集合,则下列结论中正确的是( )
A.![]() | B.![]() |
C.![]() | D.![]() |