1 . 如图,在钝角
中,
为钝角.设
的外角平分线与
过B和过C的高线分别交于点E,F,点M在线段EC上使得
,点N在线段BF上,使得
.证明:E,F,M,N四点共圆.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/854f480c60b88b546cb15d3b5622e212.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d21fa3492cd1ac2b3f9278d3fe4cd4fd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d21fa3492cd1ac2b3f9278d3fe4cd4fd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/854f480c60b88b546cb15d3b5622e212.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8cd09bf3d43769b015a0a8d5b34cdefe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/37595daefab7761a896f29f785d253d1.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/9/bc6bb557-dd54-4bd6-8e9a-982625129d7d.png?resizew=217)
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2 . 已知
是
所在平面外一点,
到
,
,
的距离相等,且
在
所在平面的射影
在
内,则
一定是
的( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
A.内心 | B.外心 | C.垂心 | D.重心 |
您最近一年使用:0次
2022-08-19更新
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333次组卷
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2卷引用:江苏省南通市通州区金沙中学2021-2022学年高一下学期期末数学试题
3 . 现有边长为
的正四面体
,其中点M为
的重心,点N,H分别为
,
中点.下列说法正确的有( )
![](https://img.xkw.com/dksih/QBM/2022/5/24/2986381346414592/2986469920751616/STEM/fc75d133-44c2-4397-82f4-98babfe4a4d9.png?resizew=168)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7ffe8515ff6183c1c7775dc6f94bdb8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d4357d5744046d4d44abb09e1ee35fcb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/661ff55b5ebbadfb600989af3cfce2fd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15a424b50eaeafa6f302ffd95476cb86.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f50b3ae183997b707d16eb4e7f6712fa.png)
![](https://img.xkw.com/dksih/QBM/2022/5/24/2986381346414592/2986469920751616/STEM/fc75d133-44c2-4397-82f4-98babfe4a4d9.png?resizew=168)
A.![]() | B.![]() | C.![]() | D.![]() |
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4 . 请阅读下列材料,并完成相应的任务.
战国时的《墨经》就有“圆,一中同长也”的记载.与圆有关的定理有很多,弦切角定理就是其中之一.我们把顶点在圆上,一边和圆相交,另一边和圆相切的角叫做弦切角.弦切角定理:弦切角的度数等于它所夹的弧所对的圆周角度数.
下面是弦切角定理的部分证明过程:
证明:①如图1,AB与
相切于点A.当圆心O在弦AC上时,容易得到
,所以弦切角
.
②如图2,AB与
相切于点A.当圆心O在
的外部时,过点A作直径AF交
于点F,连接FC.
∵AF是直径,∴
,∴
.
∵AB与
相切于点A,∴
,∴
,∴
.
![](https://img.xkw.com/dksih/QBM/2022/5/3/2971556652843008/2974950109806592/STEM/e34e22f97b164f5baf07d88ddab505fe.png?resizew=554)
(1)如图3,AB与
相切于点A,当圆心O在
的内部时,过点A作直径AD交
于点D,在
上任取一点E,连接EC,ED,EA,求证:
;
(2)如图3,已知
的半径为1,弦切角
,求
的长.
战国时的《墨经》就有“圆,一中同长也”的记载.与圆有关的定理有很多,弦切角定理就是其中之一.我们把顶点在圆上,一边和圆相交,另一边和圆相切的角叫做弦切角.弦切角定理:弦切角的度数等于它所夹的弧所对的圆周角度数.
下面是弦切角定理的部分证明过程:
证明:①如图1,AB与
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c10d461a7c0b86a2f09c2ea17f38260e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/460511579aaa077d85fe53f6bb7772d5.png)
②如图2,AB与
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7cbce11aa19b8bd2bf6ee5a834e005de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
∵AF是直径,∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e23d90078fcdfde7e9f221bc2bebda3a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/da32065b24911b830aaa9095edee6461.png)
∵AB与
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d89c5a162bd71f3b237d18d0996a6d73.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f36c57e73133469b27213ab57ce710c1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49db80c5a4f32fcd2db22bf6903ea481.png)
![](https://img.xkw.com/dksih/QBM/2022/5/3/2971556652843008/2974950109806592/STEM/e34e22f97b164f5baf07d88ddab505fe.png?resizew=554)
(1)如图3,AB与
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7cbce11aa19b8bd2bf6ee5a834e005de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/667349d99185bb045030b733352ff7fd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0bce8c7f984ded4431266d97ded4523c.png)
(2)如图3,已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5dbebd2e0b7ee2dae2612c3de832a543.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/667349d99185bb045030b733352ff7fd.png)
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解题方法
5 . 如图,在五棱锥
中,
,
,
,
,F为棱
上一点,且满足
,平面
与棱
分别交于G,H.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/26/a4238d37-bea5-45de-b120-16bb8fcf357f.png?resizew=221)
(1)求证:
;
(2)求
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be89b9d1709d7974a108142c5fa2ccec.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4207cb4606a54c615cc30541f5f8751a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8cea1fa98ed569e4e0e51df9e536da18.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a209e342226efa2d747e1990baee9bb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0e52afb0eaa29b2e542805716db11243.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc5adb5eb60ae4435a12d93854066298.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/71a0a3a2b6faaa02a7a0cac44cf9c2a3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20af148464904e21f4374cc8fb886fba.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fb46aaae98bce8e66848e09c2c1cdbd4.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/26/a4238d37-bea5-45de-b120-16bb8fcf357f.png?resizew=221)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a086b085224857d7d0c92bc5c2d6465.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1c99298cb62582a9ec6dd55b5b441f9a.png)
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6 . 已知双曲线
的左、右焦点分别为
,
,P为双曲线C右支上的动点,过P作两渐近线的垂线,垂足分别为A,B.若圆
与双曲线C的渐近线相切,则( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1d425a7131017df2ef6eb55cc7070caf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f5076289823db419f94e9c0c8f4aafd9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a3fb78c5f885034612c0e030b920143d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d9df0d79e42d86b0def4caa10dffa75a.png)
A.双曲线C的离心率![]() |
B.当点P异于顶点时,![]() ![]() |
C.![]() ![]() |
D.![]() ![]() |
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2022-04-19更新
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885次组卷
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3卷引用:山东省德州市夏津第一中学2022届高三4月联合质量测评数学试题
名校
7 . 在三棱锥
中,点Р在底面ABC内的射影为Q,若
,则点Q定是
的______ 心.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63397cda22cb1fad59cf966dfb588643.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/30fc65a72853bd8ac1ad0828270d3baf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
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6卷引用:上海市格致中学2021-2022学年高二上学期期末数学试题
上海市格致中学2021-2022学年高二上学期期末数学试题上海奉贤区致远高级中学2022-2023学年高二上学期期中数学试题(已下线)专题02简单几何体(7个考点)【知识梳理+解题方法+专题过关】-2022-2023学年高二数学上学期期中期末考点大串讲(沪教版2020必修第三册+选修一)山东省济南市长清中学2021-2022学年高一下学期5月月考数学试题(已下线)第32讲直线与平面垂直2(已下线)8.6 空间直线、平面的垂直(分层练习)-2022-2023学年高一数学同步精品课堂(人教A版2019必修第二册)
名校
解题方法
8 . 著名的费马问题是法国数学家皮埃尔·德费马(1601-1665)于1643年提出的平面几何极值问题:“已知一个三角形,求作一点,使其与此三角形的三个顶点的距离之和最小.”费马问题中的所求点称为费马点,已知对于每个给定的三角形,都存在唯一的费马点,当
的三个内角均小于120°时,则使得
的点
即为费马点.根据以上材料,若
,则
的最小值为( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1eab88a16df610f20dd46a44ba098d8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7df05e4c2e1b3f714940c1bc6b8d8c8e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b297fec84a56859dd898d85f21719e79.png)
A.![]() | B.![]() | C.![]() | D.![]() |
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873次组卷
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7卷引用:江苏省南京市2020-2021学年高二下学期四月质量检查数学试题
江苏省南京市2020-2021学年高二下学期四月质量检查数学试题(已下线)第七章 复数(提分小卷)-【单元测试】2021-2022学年高一数学尖子生选拔卷(人教A版2019必修第一册)新疆石河子第一中学2021-2022学年高一下学期4月月考数学试题(已下线)河南省南阳市2022-2023学年高三上学期期末数学(理)试题变式题11-15(已下线)微专题08 巧妙借助复数的几何意义求与模有关的范围与最值问题-【微专题】2022-2023学年高一数学常考点微专题提分精练(人教A版2019必修第二册)(已下线)第五篇 向量与几何 专题15 几何最值(费马点、布洛卡点等) 微点3 费马点、布洛卡点综合训练(已下线)第7.2.1讲 复数的加、减运算及其几何意义-同步精讲精练宝典
名校
解题方法
9 . 已知
为
的重心,且
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e5085e3cdef9ea6c564e079f745d6fdb.png)
___________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac1d6ee7b2e012c660eb9e6206db274f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e5085e3cdef9ea6c564e079f745d6fdb.png)
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2021-08-12更新
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908次组卷
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7卷引用:河北省邯郸市九校联盟2020-2021学年高一下学期期中数学试题
10 . 设
是
内任意一点,
表示
的面积,
,
,
,定义
.若
是
的重心,
,则( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b5cbff84327e964f912a54032e76ccc9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7dd6bc7f9c877dc837284375f2cfc1a7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b5de363cbdfc41d8c7a0f378a4136a5a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4f8f1ddf6b7bc01c64dfe6d937b0f863.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e6a2b6189d306f8279a20a2da4f7c10.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54e82c6712a0989cab17cac6bb475d28.png)
A.点![]() ![]() | B.点![]() ![]() |
C.点![]() ![]() | D.点![]() ![]() |
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