名校
1 . (1)证明:
.
(2)已知正数a,b,c,用反证法证明:
,
,
这三个数中,至少有一个不小于4.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ceed227c026ff8d94237c63ace92cf78.png)
(2)已知正数a,b,c,用反证法证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d5292c85c68f9b8267e9e212d4f02af2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e75211eb335491ac5bf72459a80b5728.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7b7b2877e9e163191cdca767a7ecbb3b.png)
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2 . (1)用综合法证明:设
,
均为正实数,且
,则
;
(2)用反证法证明:
在
上无零点.
![](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/22404ecc9b3ef48f2674c905008521bb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3653e6a6f083c5cd8c04acded895e376.png)
(2)用反证法证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/89285a8ffd5c563404f4fa52885ee2a9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36e02e8ca2dd39db848095a58e75b6ed.png)
您最近一年使用:0次
2021-12-01更新
|
372次组卷
|
2卷引用:广西河池市2020-2021学年高二下学期八校第一次联考数学(理)试题
3 . 已知函数
.
(1)求
的值;
(2)求证:
,
,
三个数至少有一个不小于2.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e165965f16fa180a49c024f2977df6bc.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4a461f87a3e96b374c1a6ecd831c5b11.png)
(2)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bf2c267eee6151e1fb721afcec781311.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/06edc3a74f24df928700cb03080662ef.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/94afaacb3e423336ae85e7da73333fb9.png)
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4 . 证明:
个人中至少有两人生日相同(利用反证法)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ba602bfa3a3ffb4fb43dc0f704a7f7d.png)
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解题方法
5 . 已知x为正数,a=-x+
,b=5x-
,用反证法证明:a,b中至少有一个不小于6.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1d1751f99590f9539afce484c196f719.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf35027e76f8ea593f82023973d4aba3.png)
您最近一年使用:0次