1 . 有一个由n个城市组成的王国,其某些城市之间有道路相连,满足:(1)所有道路互不相交(若某两个城市间有道路相连,则称它们相邻);(2)对任意两个城市都可以从一个城市出发沿道路走到另一个城市(中间可能通过其他城市);(3)从任意一个城市出发,如果每一条道路至多利用一次的话,一旦离开则不可能回到出发的城市.国王进行如下改革:任命改革前的n位市长中的每一位改革后仍担任市长;任命改革前相邻城市的两位市长改革后仍在某两个相邻城市任市长.证明:存在一个城市改革前后由同一个人任市长,或者存在两个相邻城市改革前后互换市长.
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2 . 设
和
为两组复数,满足:
.求证:存在数组
(其中
),使得
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/40b2f1f2faeb04505752c4c08b5d4a24.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d5b023415e27a14faac81fd5237fa1a3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/38af3182c396bef07007d4b04c92d32c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f094ba98f6c02216c714bd9ff85bd59f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/057d57358dd4fd992df26157efa5bd9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83c72aec1d89b300f5a069080cdd3e1a.png)
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3 . 对每个正整数n,定义
为从1到n中所有与n不互质的正整数的和.求证:若
且
,则
是合数.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/38fcec7af3520884b173b29bda6c657a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a9ba50ede8ef97b843accf839fef5c0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c7d9712c3b25f3030e166e136d3a4686.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ae9dd56551121a5b88be4dc6910c9ec0.png)
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4 . 如图,在
中,
,且
为
边上的高,
为
边上的中线,
为
的平分线,
与
分别交于
两点,
与
交于
点,令
.求证:
,且
是最好的界(即可以无限接近于
).
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/844bfe106baea0caf51cd2228b54dbe8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4cae70b8a9d2d2e96dea62c00ced04b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/194741f4d2ae7ee44cafca780361446a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/69995843d21aed8728363afe2fbb6462.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bc57cface1f8ce1045c96d97de692fc2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4cae70b8a9d2d2e96dea62c00ced04b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/500acc25d51dc3519a17c2ffa7fccdee.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7900d4dcf3cf3aa4e5ae000766083819.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5e6486784415f3537c9a13556c05d893.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b624e6d456c5aa077dfd00ada3a311d4.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/26/b68ec419-9dc9-469b-9b36-b6ddfdf7433d.png?resizew=199)
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5 . 如图,锐角
中,
为边
中点,
内切圆与边
切一点
的内切圆与边
切于点
,若四边形
为平行四边形,求证:
在
的平分线上.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab2a2834d80ff574e79eae8ca8d4e94f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5cbc944ca5f456dc6ece9fa58a7bbb6f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/25ae006f399a4b83fb384de288c860b0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7cbce11aa19b8bd2bf6ee5a834e005de.png)
![](https://img.xkw.com/dksih/QBM/2021/7/20/2768301525590016/2769082901225472/STEM/94a7ced5a2c04ff2879a4f42b5a76699.png?resizew=185)
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6 . 设
,记:
,其中求和是对1,2,…,n的所有
个k元组合
进行的,求证:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0610af5abf3cc278643f5696f58b625d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/12b645e448faf42a5eec1a1e02b85325.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c015bd3b114c45ca0881c8468b4b35d3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/800cc73c3cf1e852b3cb2eb9dc1ff3f7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/663211001b3f08bcbe2cf4a9c9ee0505.png)
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7 . 在平面内画出
条直线,把平面分成若干个小区域,其中一些区域涂了颜色,且任何两个涂色区域没有公共边界(可以有公共顶点).证明:涂色区域的个数不超过
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2ac19e2a797cd0a408316988a63b3755.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2866ff31ae2ffca346abd702de0d7437.png)
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8 . 设
、
是无穷复数数列,满足对任意正整数n,关于x的方程
的两个复根恰为
、
(当两根相等时
).若数列
恒为常数,证明:
(1)
;
(2)数列
恒为常数.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e976c0663fa749ca749f99842d21ca03.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80289c798034033f2f7cfcd7590f2344.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3282e5fde4ae53fcb1bb072a685304c9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3002f56900c2924bfd79fc3865b0a02e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e52cabfa2464501decf05aed007cbaf4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/841f4ea50fa0c2b4c6e47dc04597abba.png)
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/561d594ed04e6652c75dac56259f4292.png)
(2)数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
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9 . 设
为一个质数,且
也是一个质数,证明:
的小数表示形式中包含0至9的所有数码.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7ca4c3cdbb63bf2e3c1c3d67d46d3acc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6cbadc8f735cb509c99741c41f32d097.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a1eccdf91bcfb339dee1e546ebcf17bc.png)
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10 . 设
为给定的正整数,实数
及
满足如下条件:
(1)
;
(2)
;
(3)
;
(4)
.
证明:对一切
,均有
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3bcfc48f9bc23cc43085bdb910e7a136.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9304e71a623c4412188a800046a970d0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e3d172f08313520e76b6cbc2ff9980c.png)
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3a81357dc2bcd382142e2aa19a74cadd.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3785965a2dd765765ccef0330052fca7.png)
(3)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b04f7ed829546d2b2260985f507f3a8.png)
(4)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7cbe0bce8fb16093bc80ad1e0a472acf.png)
证明:对一切
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6ef835c9ad2636a9662fb6c99e3abc78.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd7a172e3de92f315198a515eef6ebbe.png)
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