1 . 设X是有限集,t为正整数,F是包含t个子集的子集族:F=
.如果F中的部分子集构成的集族S满足:对S中任意两个不相等的集合A、B,
均不成立,则称S为反链.设S1为包含集合最多的反链,S2是任意反链.证明:存在S2到S1的单射f,满足
或
成立.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0786765588f3b18613e77b96195a6445.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/19d3e6424748cc77bd3aef39b35ace1e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/88e6f124a018e222d255a355551ece79.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cca3e38ea27e79d485d2f39a634241ee.png)
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2 . 设
,
(
为常数).若
,证明:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6694500d0b3cd2784e4c9617d2d77861.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/16ff6ff5c00396b7f7d50675d80a0844.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/700458c01a7ad031e27d80ed43e9e882.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57db73d5e95d0dda392d5af3a5cecaa4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/13cb85820577e4c835a8d6a2f272ebd0.png)
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3 . 如图,椭圆
,抛物线
,设
相交于A、B两点,O为坐标原点.
![](https://img.xkw.com/dksih/QBM/2020/5/11/2460515457130496/2460965437923328/STEM/75da524c4c21407b87577dd3f778eacb.png?resizew=143)
(1)若△ABO的外心在椭圆上,求实数p的值;
(2)若△ABO的外接圆经过点
,求实数p的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f036026cd92e9ad059c3f22a7658638.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4e393b3e36390b1354950e2cfccc4967.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21e9feabc99f62ee569b460e61526e2e.png)
![](https://img.xkw.com/dksih/QBM/2020/5/11/2460515457130496/2460965437923328/STEM/75da524c4c21407b87577dd3f778eacb.png?resizew=143)
(1)若△ABO的外心在椭圆上,求实数p的值;
(2)若△ABO的外接圆经过点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03976ba1b8949d011f01facbb7135d87.png)
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2020-05-12更新
|
438次组卷
|
2卷引用:2019年全国高中数学联赛浙江省预赛
4 . 在复平面上,任取方程
的三个不同的根为顶点组成三角形,则不同的锐角三角形的数目为____________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f7fbb04dcf05e80af28956e70b346c3e.png)
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5 . 设
,数列{xn}满足
.若1≤x7≤2,则x8的取值范围为____________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a6dc6b2701de8807efd7cc22e1f21af7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68513f125e6766a039eab3ab01cce834.png)
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6 . 设
,定义
,
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c48a84bbc68327f13df6af3e8083db9a.png)
____________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5f3f3db1411700e117d64bbf38a8737.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76c3ef724cecaca2c47141a7452bad48.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3077d758b9ea826fcfbdb20312811aa9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c48a84bbc68327f13df6af3e8083db9a.png)
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7 . 如图,在△ABC中,∠ABC=120°,AB=BC=2.在AC边上取一点D(不含A、C),将△ABD沿线段BD折起,得到△PBD.当平面PBD垂直平面ABC时,则P到平面ABC距离的最大值为____________ .
![](https://img.xkw.com/dksih/QBM/2020/5/11/2460515457130496/2460965437710336/STEM/87b88735314a4c0d89f1cfab58eff00d.png?resizew=152)
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8 . 已知集合A={k+1,k+2,…,k+n},k、n为正整数,若集合A中所有元素之和为2019,则当n取最大值时,集合A=________ .
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