1 . 我国南宋数学家杨辉1261年所著的《详解九章算法》一书里给出了杨辉三角,书中是用汉字来表示的,如图1.研究发现,杨辉三角可以由组合数来表示,如图2.
杨辉三角有很多有趣的性质,如杨辉三角的两个腰上的数字都是1,用组合数表示为
.请写出一条其他的性质,用组合数表示为:______ .从杨辉三角蕴含的规律可知:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/616fbb8c7348bf0f926404bba3df3ce4.png)
______ .
![](https://img.xkw.com/dksih/QBM/editorImg/2023/8/15/7a8aca28-ce0c-498a-bc45-e5b170667a8b.png?resizew=697)
杨辉三角有很多有趣的性质,如杨辉三角的两个腰上的数字都是1,用组合数表示为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7964ea245849a99ef5ad9d30295b1329.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/616fbb8c7348bf0f926404bba3df3ce4.png)
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2 . 已知________.
(1)解不等式
;
(2)若
的解集为R,求实数b的取值范围.
从下面条件①、条件②中任选一个,补充在上面的横线上作为已知,并作答.
①
的最小值是a;
②不等式
的解集是
.
(1)解不等式
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0de9db115080b62ceb32d39f890b6d8f.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8c93a5df4808c014f0b4aeffefb3d05e.png)
从下面条件①、条件②中任选一个,补充在上面的横线上作为已知,并作答.
①
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/222d0ba81e913f1289c10e4783ce35db.png)
②不等式
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce9a91332440ae5eb3495cbc4cbd64b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f0b05849c5aa6777c65d0035f08ad96e.png)
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3 . 设
,
,
,则( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ef2a45773db8d347f0cfa4e4fca7fd5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2b486d6d9a855a8cf9ee2c69c04ae8ad.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8add3bac16eaf09b04d5a976828a561.png)
A.![]() | B.![]() | C.![]() | D.![]() |
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2023-01-13更新
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6卷引用:北京市陈经纶中学2022-2023学年高一上学期12月诊断数学试题
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4 . 根据国家高考改革方案,普通高中学业水平等级性考试科目包括政治、历史、地理、物理、化学、生物6门,考生可根据报考高校要求和自身特长,从6门等级性考试科目中自主选择3门科目参加考试,在一个学生选择的三个科目中,若有两个或三个是文史类(政治、历史、地理)科目,则称这个学生选择科目是“偏文”的,若有两个或三个是理工类(物理、化学、生物)科目,则称这个学生选择科目是“偏理”的.为了了解同学们的选课意向,从北京二中高一年级中随机选取了20名同学(记为
,
,2,
,19,20其中
是男生,
是女生),每位同学都各自独立的填写了拟选课程意向表,所选课程统计记录如表:
(1)从上述20名同学中随机选取3名同学,求恰有2名同学选择科目是“偏理”的概率;
(2)从北京二中高一年级中任选两位同学,以频率估计概率,记
为“偏文”女生的人数,求
的分布列和数学期望;
(3)记随机变量
,样本中男生的期望为
,方差为
;女生的期望为
,方差为
,试比较
与
;
与
的大小(只需写出结论).
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/50a272adba0f1120109824440f0e252c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7c45176df950dfe48b8ca7eac08ee349.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f782d70309802445202487eee751cbdd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2dc8086120dd40f8b841f0e3d674fd68.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e266dafb2e8d23f1a572abc1be2a96fd.png)
学生科目 | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() |
政治 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |||||||||||
历史 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | ||||||||||
地理 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | ||||||||||
物理 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |||||||
化学 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |||||||||||
生物 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
(2)从北京二中高一年级中任选两位同学,以频率估计概率,记
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f022950e0faa45b617d497b01b5292b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f022950e0faa45b617d497b01b5292b9.png)
(3)记随机变量
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2af47421c0539033d70024966f39835.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0924ce3e7d756f9f222752c9db8fb6af.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a961e29b5b0773f3fdb8cc7e2ceb8094.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/64bad212e1d9b641464ff6178109167e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/517ff073109a22fb321274d83412ebee.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0924ce3e7d756f9f222752c9db8fb6af.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/64bad212e1d9b641464ff6178109167e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a961e29b5b0773f3fdb8cc7e2ceb8094.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/517ff073109a22fb321274d83412ebee.png)
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775次组卷
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6卷引用:北京市第二中学2021-2022学年高二下学期期末数学试题
北京市第二中学2021-2022学年高二下学期期末数学试题北京市海淀区中国人民大学附属中学2023届高三下学期开学摸底练习数学试题北京市人大附中2023届高三下学期2月开学考数学试题北京市广渠门中学2024届高三上学期开学考数学试题(已下线)7.3.2离散型随机变量的方差(分层作业)-【上好课】2022-2023学年高二数学同步备课系列(人教A版2019选择性必修第三册)(已下线)7.3.2 离散型随机变量的方差——课后作业(巩固版)
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5 . 下列叙述中,
①等差数列
,
为其前n项和,若
,
,则当
时,
最小;
②等差数列
的公差为d,前n项和为
,若
,则
为递增数列;
③等比数列
的前n项和为
,若
,则
有最小项;
④在等差数列
中,记
,若存在
,使得
,则
为递增数列.
正确说法有______ (写出所有正确说法的序号)
①等差数列
![](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/b134439819d3069da709979cb9b1a991.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5846713aaecbab35ad985cbe9ad7d44a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd6cd3173d146902c5518503888c3b59.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
②等差数列
![](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/c4ce64685821c3e55c07f151996ca8c3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/846fa57d92d6ad44d6a0cafad1e71ed4.png)
③等比数列
![](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/ba5c8a6c196890aa7871ea0c82061ea5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/846fa57d92d6ad44d6a0cafad1e71ed4.png)
④在等差数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/134aefab10d3e81e223e9123da5f417e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f29c06a3e9a73e905eb87d71efa201c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fbb50854126e66c09294192ed1db29ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
正确说法有
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6 . 如图,在四棱锥
中,四边形
是平行四边形,点F为
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/5/97ce03fd-4ef3-4ff4-9b7e-57a3d437e222.png?resizew=210)
(1)已知点G为线段
的中点,求证:CF∥平面
;
(2)若
,直线
与平面
所成的角为
,再从条件①、条件②、条件③这三个条件中选择几个作为已知,使四棱锥
唯一确定,求:
(ⅰ)直线
到平面
的距离;
(ⅱ)二面角
的余弦值.
条件①:
平面
;
条件②:
;
条件③:平面
平面
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0629ce42392a7fe9be21d25c39c3e64.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/5/97ce03fd-4ef3-4ff4-9b7e-57a3d437e222.png?resizew=210)
(1)已知点G为线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c4180c271831327644dc83240b715b5.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f83a04565a8ebaa111894b724b0ba266.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f6b86c22b670a8e9f3896f9e8883fbbb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
(ⅰ)直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20af148464904e21f4374cc8fb886fba.png)
(ⅱ)二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a38a3e226347af68d7b15295342e209.png)
条件①:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
条件②:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a9c3ec174b1ce835cc8737ff6ce57e52.png)
条件③:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e4aa9084b8fe0fe05c4388d1f835587b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/852aabd89edffc1b94344ff3f1f31ccd.png)
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2023-01-04更新
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5卷引用:北京市西城区北师大二附中2022-2023学年高二上学期12月月考数学试题
北京市西城区北师大二附中2022-2023学年高二上学期12月月考数学试题北京市海淀区2022-2023学年高二上学期期末练习数学试题北京市中央民族大学附属中学2022-2023学年高二上学期期末数学试题(已下线)北京市海淀区2023届高三上学期期末练习数学试题变式题16-21河南省郑州市第一〇二高级中学2023-2024学年高二上学期10月月考数学试题
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解题方法
7 . 如图,在三棱柱
中,平面
平面
,侧面
是边长为2的正方形,
分别为
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/5/44e29202-58ce-4e59-a9ae-6b55a7711348.png?resizew=199)
(1)证明:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
面![](https://staticzujuan.xkw.com/quesimg/Upload/formula/72f0d0e78101fef36a75b70ac7e7cf5b.png)
(2)请再从下列三个条件中选择一个补充在题干中,完成题目所给的问题.
①直线
与平面
所成角的大小为
;②三棱锥
的体积为
;③
. 若选择条件___________.
求(i)求二面角
的余弦值;
(ii)求直线
与平面
的距离.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/91ba5715a95b8de18c637c12c3d30d7d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e168672b47d7e64dc1b404f8882c7dcf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/72f0d0e78101fef36a75b70ac7e7cf5b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d12b92bb195943c794a3b3cf135d71a0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4ddef39ef9ed3da136c4ed8b5d28b73e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/5/44e29202-58ce-4e59-a9ae-6b55a7711348.png?resizew=199)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/638537c0a30676c73fea76c80e0f8bd0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/72f0d0e78101fef36a75b70ac7e7cf5b.png)
(2)请再从下列三个条件中选择一个补充在题干中,完成题目所给的问题.
①直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e168672b47d7e64dc1b404f8882c7dcf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15615de1a6df206dbd081251f676578e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8da67af246912670bac6dc860f301383.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4dac452fbb5ef6dd653e7fbbef639484.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ff4fcf607b0710d12aaabd17fd053d83.png)
求(i)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/34ecc467cf90f9f26cf6902af77427ca.png)
(ii)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/72f0d0e78101fef36a75b70ac7e7cf5b.png)
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2023-01-03更新
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883次组卷
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3卷引用:北京市海淀实验中学2023届高三上学期期末数学试题
北京市海淀实验中学2023届高三上学期期末数学试题第八章立体几何初步章节验收测评卷-【精讲精练】2022-2023学年高一数学下学期同步精讲精练(人教A版2019必修第二册)(已下线)重难点突破02 利用传统方法求线线角、线面角、二面角与距离(四大题型)
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8 . 已知椭圆
:
和双曲线
:
有公共的焦点F1 (−3, 0),F2 (3, 0),点P是C1 与C2在第一象限内的交点, 则下列说法中错误的个数为( )
①椭圆的短轴长为
;
②双曲线的虚轴长为
;
③双曲线C2 的离心率恰好为椭圆C1 离心率的两倍;
④
PF1F2 是一个以PF2为底的等腰三角形.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1241216f3c1cb5e73043dd1037f556d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3dbc0404b2ff77232b480bce5289d7e6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/23f3ffe7abc59e2f65d827c8eab8d36a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/675c20eff35b1d3f37393850e3d7b103.png)
①椭圆的短轴长为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dbff61fe9d4e93d7cc338489d1c99c40.png)
②双曲线的虚轴长为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b91d650c2fc1a741fabdb333b09aeb6.png)
③双曲线C2 的离心率恰好为椭圆C1 离心率的两倍;
④
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce4cba95fc7d4853a243f8e3fb20ce70.png)
A.0 | B.1 | C.2 | D.3 |
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2023-01-02更新
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2卷引用:北京大学附属中学2022-2023学年高二上学期期末复习数学试题(2)
名校
9 . 已知集合
,规定:集合
中元素的个数为
,且
.若
,则称集合
是集合
的衍生和集.
(1)当
,
时,分别写出集合
,
的衍生和集;
(2)当
时,求集合
的衍生和集
的元素个数的最大值和最小值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d5de9c4ca739b182a9c449c262276570.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0704f453b2de48d36911f7db496bbf82.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/62e3fb64fd9c714eee9f5c1b3ef5c53a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
(1)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/19467f6bde28cbff6c0b48bd31955f5b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d07059e9a11aad43c2a414d018844db0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a18722354086c42e62334983fc50eb6a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cd3b9e816b14051f785aa5aae72b8eed.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7c345907ebe27888332b1b44c666cc47.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
您最近一年使用:0次
2022-12-31更新
|
390次组卷
|
2卷引用:北京市密云区2022-2023学年高一上学期(12月)数学期末试题
名校
10 . 已知
,
,给出下列结论:
①若
,
,则B的值唯一;
②若
,则
有最大值;
③若
,则
的最小值为
.
其中,所有正确的结论序号为___________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f08ce80e91fdf435a8e3ec05be990e9d.png)
①若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/65f9c88edac18a30697feb5a9956b70b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc8c65bea2c80af038768b74250c694e.png)
②若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/35e1bd4f72b3edd9647378d1191857fa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b5cbff84327e964f912a54032e76ccc9.png)
③若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e71c76949f930de79abdbddacf243b8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5201fc26d013f6fb889933c0e32f5c53.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d63d1200ef5de2c40f2022af10a87b74.png)
其中,所有正确的结论序号为
您最近一年使用:0次