1 . 在用反证法证明命题“若三个正数a,b,c满足
,则a,b,c三个数中至多有两个数小于3”时,应该反设为( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/724e3ffa8bf693be79f047bc77474a84.png)
A.假设a,b,c三个数都小于3 |
B.假设a,b,c三个数都大于3 |
C.假设a,b,c三个数中至少有两个数小于3 |
D.假设a,b,c三个数中至多有两个数不小于3 |
您最近一年使用:0次
2022-05-09更新
|
178次组卷
|
3卷引用:河南省新乡市2021-2022学年高二下学期期中考试数学(文科)试题
2 . 有限数列
:
,
,…,
.(
)同时满足下列两个条件:
①对于任意的
,
(
),
;
②对于任意的
,
,
(
),
,
,
,三个数中至少有一个数是数列
中的项.
(1)若
,且
,
,
,
,求
的值;
(2)证明:
,
,
不可能是数列
中的项;
(3)求
的最大值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d3cfeacc29e6a61c5b3b4e439c0a91df.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/96abfe2da27a63e6affb19a0c80236d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3bcfc48f9bc23cc43085bdb910e7a136.png)
①对于任意的
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c05b9832b09731a574d4a4adf7448de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7600d2cfbdc6146db96cc545706004f6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/937c09d82c480e4d67f8a48d3f66c5f5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/431acf301f0cf1e414b532de94708474.png)
②对于任意的
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c05b9832b09731a574d4a4adf7448de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7600d2cfbdc6146db96cc545706004f6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f0a532e15e232cb4b99a8d4d07c89575.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/247bf9c5c1ad2b3e50952ec92afa3ac9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9f52783e7a39f438adf08ef7d05d8c78.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a8343838b2f9943d83231763b2078136.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1be0f858adaefa50f7c99e6062fdf2ad.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d3cfeacc29e6a61c5b3b4e439c0a91df.png)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fac3649308b528fd56545ba102dc42d5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b065334d8f60c49f4bd3d9f1373fe4cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c9b6e51986fe5d7a7265e0e93adcb4d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/32ad229a63bc75abfa8f5a48fe99038f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b3859890e300f470dcf4a215249da07e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
(2)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ca7d1107389675d32b56ec097464c14.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d91e07104b699c4012be2d26160976a2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d3cfeacc29e6a61c5b3b4e439c0a91df.png)
(3)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
您最近一年使用:0次
2021-11-19更新
|
1231次组卷
|
10卷引用:北京市北京师范大学第二附属中学2019-2020学年高二上学期期中数学试卷
北京市北京师范大学第二附属中学2019-2020学年高二上学期期中数学试卷北京市第五十七中学2019-2020学年高二上学期期中考试数学试题2015届北京市海淀区高三下学期期中练习(一模)理科数学试卷重庆市缙云教育联盟2022届高三上学期第O次诊断性检测数学试题(已下线)北京市第四中学2022届高三下学期(三模)保温练习数学试题北京卷专题18数列(解答题)(已下线)北京市第四中学2023届高三数学保温测试试题北京市十一学校2022届高三下学期2月诊断数学试题北京市第八中学2024届高三上学期10月练习数学试题北京市汇文中学教育集团2023-2024学年高三下学期开学考数学试题
名校
解题方法
3 . (1)a,b,
,求证:
,
,
不能都大于1.
(2)已知
,
,
,求证:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0fa7b9037d62bde0a2fca3f7da9fc351.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a9b76fc410e367b02fa2e146ba2d854.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f280f0ed2cae448ba4791f1849b0028d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c8b33232aca52c3f4bbaa4f37ec227cb.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/5558c083d34cbb0a58d3ce1dc6f5778e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/128294be1f10b83df30ad60d4c696224.png)
您最近一年使用:0次
名校
解题方法
4 . 对于数集X={-1,x1,x2,
,xn},其中
,n ≥ 2,定义向量集
,若对任意
,存在
,使得
,则称X具有性质P.例如{-1,1,2}具有性质P.
(1)若x > 2,且{-1,1,2,x}具有性质P,求x的值;
(2〉若X具有性质P,求证:1 ∈X ,且当xn >1 时,x1= 1;
(3)若X具有性质P,且x1= 1 ,x2 =q (q为常数),求有穷数列x1,x2,
,xn的通项公式.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/daa5e9bd516f6282483b92cfe6074623.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4d0040b12a13d03d5f1c6c1f80ac0365.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4ac4d197ead9c1bc27b05aedac23ad79.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c122d308af408739c2717376e932122d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/37c6bb4424eb1e5ab02b8ac83fd6ad10.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d8de3dabcc3150fd539ac97718ba10c5.png)
(1)若x > 2,且{-1,1,2,x}具有性质P,求x的值;
(2〉若X具有性质P,求证:1 ∈X ,且当xn >1 时,x1= 1;
(3)若X具有性质P,且x1= 1 ,x2 =q (q为常数),求有穷数列x1,x2,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/daa5e9bd516f6282483b92cfe6074623.png)
您最近一年使用:0次
2021-08-29更新
|
544次组卷
|
6卷引用:北京市中关村中学2021-2022学年高二上学期期中考试数学试题
名校
5 . 用反证法证明“若
,则
至少有一个为0”时,假设正确的是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0d9899985a7d52e01fb58c4156cc4407.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/62ff2912fd8d93b6e692936d95b727c5.png)
A.![]() | B.![]() |
C.![]() | D.![]() |
您最近一年使用:0次
2022-07-09更新
|
120次组卷
|
3卷引用:广西桂林市2021-2022学年高二下学期期末质量检测数学(文)试题
6 . (1)设a,b均为正实数,证明:
.
(2)证明:2,3,
不可能是一个等差数列中的三项.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/582182c3614a61b557b0ad9f54553d10.png)
(2)证明:2,3,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d4056761b8f826eeb6ad8c9a151d3c9c.png)
您最近一年使用:0次
7 . 已知
是整数,
是偶数,求证:
也是偶数;
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c8cc0b4997cae4d8aec791a1d3923314.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
您最近一年使用:0次
8 . 已知
,
.请选择适当的方法证明.
(1)若
,证明:
;
(2)若
,证明:
与
不能同时成立.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/94440d3e4c073f94f2b266ff99d50e74.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/67ca5fd57c2c2fcc3c7a574fdd1467d9.png)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2958030ec9d7543dda1f529593a915e2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/98941347dd7ac01f5e63a6c5930dd5fa.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca27cc54ca0332245f5167488daa3408.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/656cacf9b32ce8f718dcb50bc8994593.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/04f678dde8a2f44b8eae985b11bf4b50.png)
您最近一年使用:0次
2022-05-05更新
|
286次组卷
|
3卷引用:河南省商丘市商丘名校2021-2022学年高二下学期期中联考数学理科试题
河南省商丘市商丘名校2021-2022学年高二下学期期中联考数学理科试题上海市七宝中学2022-2023学年高一上学期10月月考数学试题(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)
9 . (1)已知x,y,
,证明:
;
(2)用反证法证明:三个数中a,
,a+1至少有一个大于或等于
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/525c1a68848e95e6b419e0bbec3c0957.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a918943fc90b71338c4a075df7877ef.png)
(2)用反证法证明:三个数中a,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fd36903d563496a23ee02044eda8ce47.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0cf3f23bfec394769b4670962b219999.png)
您最近一年使用:0次
10 . 在各边长均不相等的
中,内角
的对边分别为
,且满足
.
(1)用分析法证明
;
(2)用反证法证明
为锐角.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24e0c10fb103930eabd5fa18e8f9bb06.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76f0649064a085fb74c997fb507a9b6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4e91bb4e912c5825fefe25a3ca9bf42e.png)
(1)用分析法证明
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1d0c69ba0bce4a97c8a7a0d1504deccd.png)
(2)用反证法证明
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
您最近一年使用:0次
2022-07-06更新
|
91次组卷
|
2卷引用:河南省南阳地区2021-2022学年高二下学期期终摸底考试文科数学试题