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
|
69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)
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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![]() ![]() ![]() |
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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)
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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)
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解题方法
8 . 我们知道,利用导数证明基本不等式:
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ff9adc4f9272724f0b088f3bf1340639.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/53eeb9d5984eb105da2dd992cd694a51.png)
您最近一年使用:0次
名校
解题方法
9 . 在正四棱柱
中,
是棱
上的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/20/e3934817-267b-4de9-ba13-bee91a6437a2.png?resizew=131)
(1)求证:
;
(2)异面直线
与
所成角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2eeb22102227c7baae1e0cc25aaeb61.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d88bf46ad08f9677c37eed1d0369329.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/20/e3934817-267b-4de9-ba13-bee91a6437a2.png?resizew=131)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/52ab924e3692515bd8be4c36472a959a.png)
(2)异面直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d50703c46b6153945d718b198f03b4b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/56f7ba05c54b3de1f4378f7c8eb58328.png)
您最近一年使用:0次
解题方法
10 . 如图所示,在三棱锥
中,
平面
,
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/1/a30d6c6e-28df-46d7-b5d0-873750c4c764.png?resizew=169)
(1)求证:
平面
;
(2)求点A到平面
的距离.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/41e5db1d2fd912f77923e4c120a7dc19.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c6deecf9ccb7b7879455050633219e09.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6138580b5e596a7846f6e4e738356e84.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2482abc1c772e327e7e43a862b405d3a.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/1/a30d6c6e-28df-46d7-b5d0-873750c4c764.png?resizew=169)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8d2d217e9bcd059908f117dfc4d4259.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ef796b46e68fe77b117ff0483d2370c.png)
(2)求点A到平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ef796b46e68fe77b117ff0483d2370c.png)
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