1 . 设
为正整数,
,
,令![](https://staticzujuan.xkw.com/quesimg/Upload/formula/649309617a29d1b9d4b2373d3c1c2946.png)
.求证:存在
使得
,
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4887473a8091e1ef53a169cc9f211e3a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4e65369cec2aac72a87c314f4c7ba143.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0be022d2478bb5f67d3e98f1319ea821.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/649309617a29d1b9d4b2373d3c1c2946.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/264d2ca5912fe1d6c354d7b0fd5efe4f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/00a28be4d5a16cf245f6fa7c4088fee4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c0f7741f4975d9df3daa0c1cdd23c9df.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/264d2ca5912fe1d6c354d7b0fd5efe4f.png)
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2 . 如图,已知
、
、
、
四点共圆,四边形
是平行四边形,
是
与
的交点,
.证明:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1bcaadfa991b0edf9163751f42d39b54.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60dc9f8e47e78b7f4ab2dd9cd559f601.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0914b68f106a912420705b2f3928ca42.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce1132157a33c82610c2d5035493d024.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/289d7a880379d6060065c829b45b0ed6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/655b6a742dbacdab5aaa298007663dd4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/06e322e0c87479bba874db9ae9ba36b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9005a613eaecad3406f9818fb278357c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1bcaadfa991b0edf9163751f42d39b54.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/25/434c7151-f90e-4ae0-ba47-2a6ccd55c11c.png?resizew=205)
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3 . 已知
、
、
都是正数,且
.
求证:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d053b14c8588eee2acbbe44fc37a6886.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e81e59019989b7dc2fb59b037ef6e010.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ff87256fdc337d698e6a9b9ebb48ea51.png)
求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1d19dd46c292deb2b5113f9012b760ee.png)
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名校
4 . 如图,在四棱锥
中,
平面ABCD,四边形ABCD是菱形,
,
,E是PB上任意一点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/24/581c5ac5-aba7-4df4-80b6-a2337cdc78dd.png?resizew=230)
(1)求证:
;
(2)已知二面角
的余弦值为
,若E为PB的中点,求EC与平面PAB所成角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a1b49f64e0065edad868b25e9fcada3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bb5b12692517a39c320f99a479eb055.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1719410d21e3de1242366ce2965e838c.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/24/581c5ac5-aba7-4df4-80b6-a2337cdc78dd.png?resizew=230)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0b757706eee506a078fc25e3f33a70cb.png)
(2)已知二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0c5651e38293e0c42a7278af69fa53ae.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83303d3784492506fc44f2b4d6b07bc1.png)
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2022-09-29更新
|
1062次组卷
|
12卷引用:广西陆川县中学2016-2017学年高二下学期知识竞赛数学(理)试题
广西陆川县中学2016-2017学年高二下学期知识竞赛数学(理)试题广西2023届高三上学期开学摸底考试数学(理)试题2015届湖南省长望浏宁四县高三3月调研(一模)考试理科数学试卷四川省成都市第七中学2016-2017学年高三下学期零诊模拟数学(理)试题四川省成都市第七中学2017-2018学年高二上学期第一次月考数学(理)试题浙江省嘉兴市平湖市2020届高三下学期5月模拟考试数学试题重庆市九龙坡区2021-2022学年高二上学期期末数学试题黑龙江省牡丹江市第二高级中学2022-2023学年高三上学期第三次阶段性测试数学试题(已下线)考向28利用空间向量求空间角(重点)广东省揭阳市普宁市华侨中学2023届高三上学期11月期中数学试题江西省南昌市新建区第二中学2024届高三上学期8月开学学业水平检测数学试题广东省河源市龙川县实验中学2024届高三上学期第二次月考数学试题
5 . 如图所示,设k>0且k≠1,直线l:y=kx+1与l1:y=k1x+1关于直线y=x+1对称,直线l与l1分别交椭圆
于点A、M和A、N.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/1/de2a14e9-1b7a-4097-971d-d543239d8a57.png?resizew=166)
(1)求
的值;
(2)求证:对任意的实数k,直线MN恒过定点.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8868e2ba4401d727f1bcb1f5483b48f5.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/1/de2a14e9-1b7a-4097-971d-d543239d8a57.png?resizew=166)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ec01614eda195be40a7d5fd494f7f344.png)
(2)求证:对任意的实数k,直线MN恒过定点.
您最近一年使用:0次
2020-05-11更新
|
616次组卷
|
2卷引用:2019年全国高中数学联赛广西壮族自治区预赛
6 . 设
.求证:
(1)
;
(2)
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dab799bf7d8290d0b33931ac58bf4bae.png)
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/04951e8f8d642b4d7fa2e7ad21f1b5f1.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aa636f1d62d1656977b079f46832bf81.png)
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7 . 如图所示,AD、AH分别是△ABC(其中AB>AC)的角平分线、高线,点M是AD的中点,△MDH的外接圆交CM于点E.求证:∠AEB=90°.
![](https://img.xkw.com/dksih/QBM/2020/5/11/2460512735158272/2460659921141760/STEM/e054184b89a14212b0f3cb3c02bbb08b.png?resizew=179)
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8 . 设
为非负数,求证:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a9ef6a16ec8802b2271d1e4d5cf87c6f.png)
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9304e71a623c4412188a800046a970d0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a9ef6a16ec8802b2271d1e4d5cf87c6f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d9d3aeb20017d60244b090bb862f4b62.png)
您最近一年使用:0次
9 . 某县位于沙漠地带,人与自然长期进行顽强的斗争,到1998年底全县的绿化率已达到30%.从1999年开始,每年将出现这样的局面,即原有沙漠面积的16%将被绿化,与此同时,由于各种原因,原有绿化面积的4%又被沙化.
(1)设全县面积为1,1998年底绿化总面积为
,经过n年后绿化总面积为
,求证:
.
(2)至少需要多少年的努力,才能使全县的绿化率超过60%?(年取整数,lg2=0.3010)
(1)设全县面积为1,1998年底绿化总面积为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/14f48a6e89f0a530b996c8e1a9c0c2e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/090426eb29836bc30c006b3739c08057.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0976f5e4d3a3ee1ab85f76ceb8ae638b.png)
(2)至少需要多少年的努力,才能使全县的绿化率超过60%?(年取整数,lg2=0.3010)
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