解题方法
1 . 已知幂的基本不等式:当
,
时,
.请利用此基本不等式解决下列相关问题:
(1)当
,
时,求
的取值范围;
(2)当
,
时,求证:
;
(3)利用(2)证明对数函数的单调性:当
时,对数函数
在
上是严格增函数.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1d33da711e50e96568facb18cef27165.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1419108104429f6df5d5352a05211e36.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/db5e0630a1632f6368fb824ebfdead0d.png)
(1)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7326ea56be82bd616fec7e6aa3c884c8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1419108104429f6df5d5352a05211e36.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca16bee4a8ecee60c31f9aaac02539b0.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1d33da711e50e96568facb18cef27165.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/27eb687fdf1568ab06ce8119845823c9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c92098b3da769963a2320cf1d8dad00a.png)
(3)利用(2)证明对数函数的单调性:当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1d33da711e50e96568facb18cef27165.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/82869dad28f771d088772a2c2b08b187.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d562dc22dfb3b81d0c3f88b54d063c2f.png)
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2 . (1)设
,
,求证:
;
(2)已知
,
,且
.证明:
或
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/94440d3e4c073f94f2b266ff99d50e74.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/67ca5fd57c2c2fcc3c7a574fdd1467d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54d8bf9316bb1dfb0559333ce56b35a6.png)
(2)已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08115d6d9f876dea921a4d32260ff1fb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/061813f1ec633c5c4c393c4de7938322.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6f9e131cdd242d56b6dba05ab3363ef3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef8e5b510c343f9d3d626fa1a4b36bad.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e36ffaf917dcebc8719f2ca539a774ec.png)
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名校
解题方法
3 . (1)已知实数
,
满足
,求证:
.
(2)若实数
,
为正数,且满足
,用反证法证明:
和
中至少有一个成立.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c94bb12cee76221e13f9ef955b0aab1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/432d77fe5ad3032d59a237dd94c8a638.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/838b9f49811c77cbf7d12d3af4a63373.png)
(2)若实数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c94bb12cee76221e13f9ef955b0aab1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4a7dbc702617c765a573961953cc0901.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eba1d7973f41f2050afd1759a0e480e4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7dfd31530f4f4d297248c3e39f42d8fb.png)
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4 . (1)
为实数,求证:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/04f25298d03745e6d91799449ed9e96a.png)
(2)用分析法证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76f0649064a085fb74c997fb507a9b6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/04f25298d03745e6d91799449ed9e96a.png)
(2)用分析法证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2b492c09f576ab6491af4848ce7ecec4.png)
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5 . 用反证法证明命题“已知x、
,且
,求证:
或
”时,应首先假设“______ ”.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/91792ac4262a83e082aa03d6d66c437a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6f9e131cdd242d56b6dba05ab3363ef3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0fde64f4d3c38e43fbdee24eadc4b0dd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eec336faee8689281a6f6b465e7fcff9.png)
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2023-03-10更新
|
252次组卷
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8卷引用:上海市崇明区2022-2023学年高一上学期期末数学试题
上海市崇明区2022-2023学年高一上学期期末数学试题上海市嘉定区2022-2023学年高一下学期3月调研数学试题(已下线)1.2 常用逻辑用语-高一数学同步精品课堂(沪教版2020必修第一册)(已下线)专题04常用逻辑用语-【倍速学习法】(沪教版2020必修第一册)上海市上海外国语大学附属浦东外国语学校2023-2024学年高一上学期期中考试数学试卷上海市松江区2023-2024学年高一上学期期末质量监控数学试卷 陕西省宝鸡市金台区2022-2023学年高二下学期期中文科数学试题青海省海南藏族自治州高级中学2022-2023学年高二下学期期末考试数学(文)试题
6 . (1)已知实数
满足
,求证:
.
(2)已知实数
满足
,用反证法证明:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/632244ea6931507f8656e1cc3437d392.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/432d77fe5ad3032d59a237dd94c8a638.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2128a00f52af4427721f0ebba591daa.png)
(2)已知实数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/632244ea6931507f8656e1cc3437d392.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/127a0d8c1c7d15ed40ec4b8bca0ebdf6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/485a2d99320384a0857b00ce9ab9e990.png)
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解题方法
7 . 选用恰当的方法证明下列不等式
(1)证明:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/679e658fa5679ce73e1b5fdfe434b724.png)
(2)已知
,证明:
.
(3)已知a,b,c均为正实数,求证:若
,则
.
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/679e658fa5679ce73e1b5fdfe434b724.png)
(2)已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73254f32b6da29ecc32df2e9f87a4c97.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5fa4f85f4d4f4bd9edaa8a964565ca1a.png)
(3)已知a,b,c均为正实数,求证:若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1a57e060f61f7efa54982bda67db483a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/22d54c9eb01acfe09c34cb808326cc5e.png)
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8 . (1)已知正数a,b,c满足
,求证:
.
(2)已知
,
,
,用分析法证明:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1a57e060f61f7efa54982bda67db483a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9070c818e51d19f4ff4e9e16091dd5cc.png)
(2)已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/94440d3e4c073f94f2b266ff99d50e74.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/67ca5fd57c2c2fcc3c7a574fdd1467d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5be97cd1c7111b654d87d8fbb63b6a84.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d4dcc5d823c113fcd61c4b7e9639a5a9.png)
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名校
9 . 已知
为实数.利用反证法证明“已知
,求证:
中,至少有一个数大于20"时,首先要假设结论不对,即就是要假设( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/874781ab5711bff6ee8c9cbad5b3b3dc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b7267291073b77eab69d5d01383c045d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/874781ab5711bff6ee8c9cbad5b3b3dc.png)
A.![]() | B.![]() |
C.![]() | D.![]() |
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解题方法
10 . 我们用
,
,
,…,
(
,且
)表示n个变量,就如同a、b、c、d、e、f等表示变量一样.已知
,
,
,…,
(
,且
)均为正数.
(1)求证:
;
(2)求证:
;
(3)请将命题(1)、(2)推广到一般情形(不作证明).
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e72adb45c60c2f63b46e65ff787302bf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e88093a749c0d46e0ee931ecfaff925.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c1ccc6c74b8754e9bcbb3f39a11b6f1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96abfe2da27a63e6affb19a0c80236d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/65a40142c84be68ee2918c3a8303388c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/59b2400d72b1e3145cb21ba719d8a968.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e72adb45c60c2f63b46e65ff787302bf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e88093a749c0d46e0ee931ecfaff925.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c1ccc6c74b8754e9bcbb3f39a11b6f1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96abfe2da27a63e6affb19a0c80236d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/65a40142c84be68ee2918c3a8303388c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/59b2400d72b1e3145cb21ba719d8a968.png)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2835f07a67db24eb20565e1e32f2aa1f.png)
(2)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9f4a1d6f90410fc3218dd4592465d647.png)
(3)请将命题(1)、(2)推广到一般情形(不作证明).
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