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1 . 用反证法证明命题“若
,则
或
”,则应假设____________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/55f9bf034aa02b5488c815517f13df3f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7ccaa6e503b61e9ae78d8439cba2e328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a15e5652f093c9852223499350d805a1.png)
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2023-10-13更新
|
131次组卷
|
2卷引用:上海市行知中学2023-2024学年高一上学期第一次质量检测数学试题
解题方法
2 . (1)已知实数a、b满足
, 证明: a,b至少有一个不小于1.
(2)若不等式
对于一切实数x都成立,求实数a的取值范围.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f1a2cbcc1fb41a01668f1808267df4d.png)
(2)若不等式
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3b56faaf0c9eee7ee0cebbd3416dbc9f.png)
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3 . 用反证法证明“若
,则
或
”时,应假设_______________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8034dddd265a186e29172623e3b9eadf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef00713e73b8357cc7900144f5505bc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e55aa0a20848c37c1892c567b2315e04.png)
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名校
4 . 用反证法证明“
,若
,则
”时,应先假设__________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/360ff131c51a4ef6745538c18cec92c2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/32378da61ce0df3dd46ccc77e906009e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48adb8a59b5c02fad5eada1b35171cf3.png)
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2023-10-11更新
|
121次组卷
|
3卷引用:上海市曹杨第二中学2023-2024学年高一上学期第一次月考(10月)数学试题
5 . 证明:
是无理数.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7ffe8515ff6183c1c7775dc6f94bdb8.png)
您最近一年使用:0次
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6 . 对于定义在
上的函数
如果同时满足以下三个条件:①
;②对任意
成立;③当
时,总有
成立.则称
为“理想函数”.有下列两个命题:
命题
:若
为“理想函数”,则对任意
,都有
;
命题
:若
为“理想函数”,则对任意
,都有
成立.
则下列说法正确的是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e11f4ca0e7ace69f92130d0525bcdb3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09f86f37ec8e15846bd731ab4fcdbacd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/249a976e88133f3b3733f09137cf5c42.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e41e188f97515c589454c51fb8e751b3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/27d5ef9e6f5429c22535001e95d726d3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b9f6988640a0b9bc4f9637132e6ca470.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09f86f37ec8e15846bd731ab4fcdbacd.png)
命题
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09f86f37ec8e15846bd731ab4fcdbacd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f3b39bbfd4894f4d2ca18473a3e42f82.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61ee7abd882ba99660bca68ebf544cd6.png)
命题
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b5858ee1ce52b251816757257a11c29.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09f86f37ec8e15846bd731ab4fcdbacd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f7dbb416ec1ff1984a724a4f48bf692.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09d3c756a52c9185ae6d02d9b9312f29.png)
则下列说法正确的是( )
A.命题![]() ![]() |
B.命题![]() ![]() |
C.命题![]() ![]() |
D.命题![]() ![]() |
您最近一年使用:0次
7 . (1)设
,
,比较
与
的值的大小关系;
(2)已知
,
,
,其中
、
、
为实数,请用反证法证明:
、
、
中至少有一个为正数.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6b41d84627f6229005178c8b69d5d401.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c925be255ca736a53b24d13ddede1a86.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76d18e9ca603e7d02cf1788acdf105f2.png)
(2)已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/651b911b5b89924a9f1715d847e9d419.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76a130665c0842c5594882a282eab790.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0446cabe6eef4e5012d0bcf2be336f06.png)
![](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/071a7e733d466949ac935b4b8ee8d183.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
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8 . (1)已知a、b都是有理数,满足
,请用反证法证明:
.
(2)已知
、
是一元二次方程
的两个不同实数根,是否存在实数k,使得
成立?若存在,求出k的值;若不存在,请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4cf9571afe259c22906605b2abcf4f4d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/657435e1fda84118e7f63c97505c8b75.png)
(2)已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c814128ea2139e33db94ea590e7c2223.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aec19b68e3add9d5bfcc6269a1855b87.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f0c6daf1a5448f998b383b980ac66596.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/47613e291693d72884fb89a2e198d6c8.png)
您最近一年使用:0次
名校
9 . (1)已知
,用反证法证明:若
,则
中至少有一个小于
;
(2)已知
,判断 “
”是“
中至少有一个小于
”的什么条件?并说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f3eb9b6fe8959ae9e71e857b6d6fed49.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63381c4b8fb5ecfd04af2808a99dca46.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76f0649064a085fb74c997fb507a9b6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4dac452fbb5ef6dd653e7fbbef639484.png)
(2)已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f3eb9b6fe8959ae9e71e857b6d6fed49.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63381c4b8fb5ecfd04af2808a99dca46.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76f0649064a085fb74c997fb507a9b6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4dac452fbb5ef6dd653e7fbbef639484.png)
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10 . 设
.用反证法证明:若
是奇数,则
是奇数.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8bf910f82c3094b267a3d481d23d829f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411a315870ed3e6d0e8ea885f1a04bcf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
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