名校
解题方法
1 . 问题:已知
均为正实数,且
,求证:
.
证明:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c09f3f04837fc78c3a8cd615d0fa4957.png)
,
当且仅当
时,等号成立.
学习上述解法并解决下列问题:
(1)若实数
满足
,试比较
和
的大小,并说明理由;
(2)利用(1)的结论,求
的最小值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76f0649064a085fb74c997fb507a9b6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/751e274e9107d780c39ba9c49d6daefb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/135125d796a469155fc4a22dc6be3d10.png)
证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c09f3f04837fc78c3a8cd615d0fa4957.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d6ce8e7fbb4c8c728f548bb6c3ae8541.png)
当且仅当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc07ff9c2cb23cfe630c7785ba7ed93b.png)
学习上述解法并解决下列问题:
(1)若实数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2edfccf9159bb4010669e938f788149b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/19f3fa0b40fb0d9b8c62e37316ab3b04.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a09ffc1644c7029219b88232145abbdf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/47e32a3a39e310fe224a979e0cafce49.png)
(2)利用(1)的结论,求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eace9aecb35ea07662a7f4fe7f75a856.png)
您最近一年使用:0次
2023-11-13更新
|
68次组卷
|
2卷引用:福建省厦门市厦门大学附属科技中学2023-2024学年高二上学期11月期中考试数学试题
21-22高二上·福建厦门·开学考试
名校
解题方法
2 . 如图,已知点P是平行四边形
所在平面外一点,
平面
,M,N分别是
,
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/15/9da13165-bb73-4ae3-83d7-6e65a4e640be.png?resizew=139)
(1)求证:
平面
.
(2)试在
上确定一点Q,使平面
平面
,并证明你的结论.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/15/9da13165-bb73-4ae3-83d7-6e65a4e640be.png?resizew=139)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7592c4f01c8e06c7ee90df5b9413a9f5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/852aabd89edffc1b94344ff3f1f31ccd.png)
(2)试在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/86d6772f5331cf0cc5302123e4698ec5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
您最近一年使用:0次
3 . “已知函数
,求证:
与
中至少有一个不小于
.”用反证法证明这个命题时,下列假设正确的是
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2bdc8676a7dd37956803566467fe2603.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03e0b7c387e1a0beaa218bb5dc659d9a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c3afed81feb2e5c366813e0bd43f432e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f89eef3148f2d4d09379767b4af69132.png)
A.假设![]() ![]() | B.假设![]() ![]() |
C.假设![]() ![]() ![]() | D.假设![]() ![]() ![]() |
您最近一年使用:0次
4 . 用分析法证明:已知
,求证
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a0c4c098615c6bc7e6dcf72e5b5201a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e131888be1afea141a1bf52fd0b1d146.png)
您最近一年使用:0次
11-12高二下·福建福州·期中
5 . 如图所示,
平面
,
,过点
作
的垂线,垂足为点
,过点
作
的垂线,垂足为
,求证:
.以下是证明过程:
要证
,
只需证
平面
,
只需证
(因为
),
只需证
平面
,
只需证 ① (因为
),
只需证
平面
,
只需证 ② (因为
),
由
平面
可知上式成立,
所以
.
把证明过程补充完整①___________ ;②__________ .
能力提升
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/10c83f8945042b9c8fb2fbdac9308d62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/080db3af81b29ed10144a1c2e2a4fb8a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d4db9b82b67efe45a02fca32bfcf5dc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c2bc5e50b8dfa02601c70822252854a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/046ced38ceae712960aca9cbf395017a.png)
要证
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/046ced38ceae712960aca9cbf395017a.png)
只需证
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c6deecf9ccb7b7879455050633219e09.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b03428a8f91a5674cb8f54766c165f7e.png)
只需证
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e40f5583fbfcac922c8ec238c0438452.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d8b73523ef27a2e5f805ae49bd304ba4.png)
只需证
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9f4c3f9dd5d0343597a7f58a1989b537.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21665d21bbfb04410c78345de1fd15ae.png)
只需证 ① (因为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c152ac8535e5e141342fc11529599841.png)
只需证
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2ffc6952e988d04f22f0fb2f7f0ab7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bc9c9cfa597b444b5c9dbae7a825a695.png)
只需证 ② (因为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/080db3af81b29ed10144a1c2e2a4fb8a.png)
由
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/10c83f8945042b9c8fb2fbdac9308d62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
所以
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/046ced38ceae712960aca9cbf395017a.png)
把证明过程补充完整①
能力提升
![](https://img.xkw.com/dksih/QBM/2018/11/27/2084571035803648/2084651543535616/STEM/79fc1473efcd4ba19a1ea2fe30e3c4c7.png?resizew=149)
您最近一年使用:0次
解题方法
6 . 已知
的三个内角A,B,C的对边分别为a,b,c,且
.
(1)求证:
为等腰三角形;
(2)若
,求
的面积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b0e65f3ca149022d8a0ee5f70e9fa776.png)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/35639227440e8dc58074332230523d9c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
您最近一年使用:0次
解题方法
7 . 如图,正方体
的棱长为2,E为
的中点.
的体积;
(2)求证:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/22adbc0da438220f9cace11b629d799b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b565e518d475a50358fedff2f0bb8dec.png)
(2)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8cb8c3e6d8e2843a2783a409e130bc0a.png)
您最近一年使用:0次
名校
8 . 如图,在三棱锥
中,
为正三角形,平面
平面
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/12/28127681-d04b-4d6c-bf58-2852053953be.png?resizew=168)
(1)求证:
;
(2)若
是
的中点,求直线
与平面
所成角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d4357d5744046d4d44abb09e1ee35fcb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7ac451db3443cabb204f96c31fd4a02e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/17580410bf63dba4fe164265afaac4cc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5e9c515dc5337d5ed8afe3f81b68c57a.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/12/28127681-d04b-4d6c-bf58-2852053953be.png?resizew=168)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d900531973c546625694146fa1509ab9.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c09afc70f448545336304333d5b5658b.png)
您最近一年使用:0次
2023-12-11更新
|
1478次组卷
|
7卷引用:福建省龙岩市第一中学2023-2024学年高二上学期第三次月考数学试题
福建省龙岩市第一中学2023-2024学年高二上学期第三次月考数学试题云南省沧源佤族自治县民族中学2021~2022学年高二上学期期末考试数学试题陕西省渭南市高级中学2023-2024学年高二上学期12月月考数学试题(已下线)高二上学期数学期末模拟卷(一)-2023-2024学年高二数学同步精品课堂(北师大版2019选择性必修第一册)云南省昆明市第三中学2023-2024学年高二下学期第一次综合测试数学试卷6.3 空间向量的应用 (5)江西省宜春市丰城市第九中学2023-2024学年高二上学期期末考试数学试题
9 . 如图,在长方体
中,E,M,N分别是
,
,
的中点,
,
.
(1)求证:
∥平面
;
(2)试确定直线
与平面
的交点F的位置,并求
的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e539f26ed5e0b20ff7220559324869a4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b7d64fc81c857b124268609a8beb77b6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcd0ced286a0fbc7e4862f8147264277.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/5/a739c35f-401f-4339-9054-6e96001a64f5.png?resizew=160)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ebb05874eb3353d754af24c9974273e.png)
(2)试确定直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0a851907ada2ac2c3c4880a6736d28a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/193b5b41994c2a4dfa5bb0bc984061cc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/274cf35acb4a1748d15c39d15a9bea7b.png)
您最近一年使用:0次
2023-11-12更新
|
149次组卷
|
2卷引用:福建省连江黄如论中学六校联考2023-2024学年高二上学期期中数学试题
名校
10 . 如图,棱锥
的底面
是矩形,
平面
,
,
.
平面
;
(2)求直线
与平面
夹角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c3b10835116b9b777a666b438c907b49.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e46571701ccaa18d3c844ab99ee6c30e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a5928c98b341b16d4b5a5b931d2929d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0628681907ac8d7fdb94d8bc1b15feb9.png)
(2)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2cdba1337ec85fa9722cb4b320a82ae6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80f747eb5b2d21c9de962cbfd4ec4bb7.png)
您最近一年使用:0次
2023-11-09更新
|
618次组卷
|
5卷引用:福建省泉州市永春第二中学2023-2024学年高二上学期12月月考数学试题
福建省泉州市永春第二中学2023-2024学年高二上学期12月月考数学试题湖南省常德市汉寿县第五中学2023-2024学年高二上学期期中数学试题广东省佛山市南海区桂华中学2023-2024学年高二上学期12月月考数学试题山东省济宁市微山县第二中学2024届高三上学期第三学段教学质量检测数学试题(已下线)湖北省七市州2024届高三下学期3月联合统一调研测试数学试题变式题11-15