1 . 如图,已知圆O是
的外接圆,切线
交于点P,D是
的中点,K、L分别在线段
上,且满足
,连结
,求证:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d79f6bec0d2dab9b9efedfe86d1159b1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f0d54431bbb28ebd98db5c1dc6083a75.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6fba0916254a96c1f639f5e82a31ff66.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/31c5702fdb97ae60c1fe843d411c309c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5e7ced0f8693546564ff0c3cae34a5b9.png)
![](https://img.xkw.com/dksih/QBM/2021/7/20/2768306466627584/2769064127176704/STEM/c6edafde048243eb9ffac9be34ca1d69.png?resizew=171)
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2 . 如图,锐角
的外接圆为
,D是A在
上的射影,假设
,点M为
中点,
的角平分线与
交于点N,
上一点P满足
.直线
与
交于点F,直线
与圆
再交于点Q.直线
与
的外接圆再交于点E.证明:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4bcd8ee2d8367c167d6ae0abc741b6b8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e8d2530e7023b2345c651e8f53629ff1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e52a8f07834cbbbe4224962672fbbb2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3981e7286d41960daf4e110c1c84e03a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4bcd8ee2d8367c167d6ae0abc741b6b8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/745cd464c272fc1e45254682591b0405.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b3533837e3d08c461dea031a44e5424d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d50703c46b6153945d718b198f03b4b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4fb26d84907c923278ac4626a9d58947.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4bcd8ee2d8367c167d6ae0abc741b6b8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/797e43acfc591c6493bb06de927aeffd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0c6ef3581369b6b5b374c1301e4d2ed3.png)
![](https://img.xkw.com/dksih/QBM/2021/7/20/2768310052290560/2809301599690752/STEM/c505ba87bb994159b998eafd242dff71.png?resizew=267)
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3 . 已知
是两个整数集合,且对于任意整数
,存在唯一的
使得
.记
.证明:对任意的
,存在
,使得
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20acd504c39502c6f09eb356b526de92.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1a6ec3553aa6ac48a909ad93263c174b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab09d975196e05808f811695b4f4af6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7b8525cb251f2e9d98691873e9cd4de6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3c41c277675b413bbff28387082c9785.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c2ba1ef1d54121f25edbe4f219b8941.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1b2fcaf03b6fbfa8d111e8bb94687e63.png)
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4 . 平面上有n个点,其中无三点共线,将这n个点两两相连,用红、黄、绿三种颜色染这些线段,且任意三点所成的三角形的三条边均恰好有两种颜色,证明:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/120af59404717873e2edb3e14774f2da.png)
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5 . 如图,已知锐角
的外接圆为
,过B、C分别作圆
的切线交于点P,P在直线
、
、
上的投影分别为D、E、F,
的外接圆与
交于点N(不同于点D),A在
上的投影为M.求证:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b454cdb97c408300b50d945f002c2cb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b454cdb97c408300b50d945f002c2cb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/72cb97395ebc5ee1b212afb7a97b985c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20a7847bff0073127f10ec3925127414.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/2/2d628892-5769-41da-9d8f-5accddf80b11.png?resizew=178)
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6 . 已知圆
与抛物线
交于A、B、C、D四个不同的点,且
为圆
的直径,线段
和
的中点分别为M、N,求证:线段
在y轴上的投影长度为定值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b454cdb97c408300b50d945f002c2cb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/344ccbf79da6ad7e3709d6fa72efb756.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b454cdb97c408300b50d945f002c2cb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
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7 . 证明:对任意正整数
,都存在正整数
和
个互不相同的正整数
,使
是完全平方数.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1563da7b0f046a469476668a3686e8f9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1fe1c31a81f198c443e71b83ca662939.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9cdc0ee2a438b747bf35b7cf4541b0f7.png)
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8 . 如图,在锐角
中,已知点D、E、F分别是点A、B、C在边
、
、
上的投影,
、
的内心分别为
、
,
、
的外心分别为
、
,证明:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9abaeba15f3abdd877bc701af52c5cd9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c105d6ba18fbb0581fb982175e2eac9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d7e64c953aaf341e772a5fe776fbc78a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2f1ac49b4139636fb1809fe970b23a87.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d1a0fd1ad044a9ecfcba672779bd678.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11d42c1c1ec9ae9cbe441a4f3df06322.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/246140da4fea6ffd1ce81dfca1238cda.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/23f919bd3dde10dbbc076f7ec5149699.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3c4f6f74444b2b7947fc6e35c8d62322.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3f45fb5ae074e506b4e9adfc20608eb4.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/31/bf3c5f9d-c1ca-4897-bc40-aa63e9bf282b.png?resizew=202)
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9 . 如图,在平行四边形
中,
、
分别是边
上的点,线段
、
交于点P,
和
的外接圆的第二个交点Q位于
的内部.证明:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a18722354086c42e62334983fc50eb6a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1241216f3c1cb5e73043dd1037f556d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3355e2fa0ac6c675f02ee36c3ced4f2d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24bb49fdc6b6bbb2449fdf8a0de769d3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cabe764f05300ac83c7d16b685d27af4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a9a02f2934a771b11ef1b1b5b68776c8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2abc4086606fca8051b61a03bf0d8217.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7ac451db3443cabb204f96c31fd4a02e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6772caf1de6f75b00f8d6dcb95f32733.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/16/8ad48411-7ba8-4b21-813e-e816298ecce5.png?resizew=241)
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10 . 已知非空正实数有限集合A,定义集合
,证明:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7b65fc3cd4d73993db28934c2584ba44.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/33da439cbb5d0c47765d0009f80fa969.png)
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