1 . 用反证法证明命题:“已知
,若
不能被
整除,则
与
都不能被
整除”时,假设的内容应为( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a6df88793c2971fc0e4c7c545740563a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/18f0281e6bbdbe08beeccb55adf84536.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b06e95b57b7a81cd81d05557a11fa92.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/8b06e95b57b7a81cd81d05557a11fa92.png)
A.![]() ![]() | B.![]() ![]() |
C.![]() ![]() | D.![]() ![]() |
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2 . 应用反证法推出矛盾的推导过程中,要把下列哪些作为条件使用( )
(1)结论的否定;(2)已知条件;(3)公理、定理、定义等;(4)原结论.
(1)结论的否定;(2)已知条件;(3)公理、定理、定义等;(4)原结论.
A.(1)(2) | B.(2)(3) | C.(1)(2)(3) | D.(1)(2)(4) |
您最近一年使用:0次
名校
3 . 用反证法证明命题“设
,则方程
与
至少有一个实根”时要做的假设是___ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73254f32b6da29ecc32df2e9f87a4c97.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/88ffc83b103ff29143b70ca14b44c37c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf7587601e702f09291a082ef1141b59.png)
您最近一年使用:0次
2022-11-08更新
|
121次组卷
|
2卷引用:宁夏银川市贺兰县景博中学2022-2023学年高二上学期第二次月考数学(理)试题
4 . 命题“若
且
,则
中至少有一个大于1”用反证法证明时应假设___________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/773ca22fc12ade9e60dbc749ba5cfa73.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/69bbd0aae5a4f6129fc78f88f662f092.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/632244ea6931507f8656e1cc3437d392.png)
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5 . 对于问题“设实数
满足
,证明:
,
,
中至少有一个不超过
”.甲、乙、丙三个同学都用反证法来证明,他们的解题思路分别如下:
甲同学:假设对于满足
的任意实数
,
,
,
都大于
.
再找出一组满足
但与“
,
,
都大于
”矛盾的
,从而证明原命题.
乙同学:假设存在满足
的实数
,
,
,
都大于
.
再证明所有满足
的
均与“
,
,
都大于
”矛盾,从而证明原命题.
丙同学:假设存在满足
的实数
,
,
,
都大于
.
再证明所有满足
的
均与“
,
,
都大于
”矛盾,从而证明原命题.那么,下列正确的选项为( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76f0649064a085fb74c997fb507a9b6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d1f9223bc24df8d429d743692fff7c06.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a13880b9454c5942f164d934b1834783.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/176400fc97133ee3a7bba932544318ea.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bb00b6918dfb251c1a63acdc07464b92.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8d5989c84e320b504511f23eeb6e7357.png)
甲同学:假设对于满足
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d1f9223bc24df8d429d743692fff7c06.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76f0649064a085fb74c997fb507a9b6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a13880b9454c5942f164d934b1834783.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/176400fc97133ee3a7bba932544318ea.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bb00b6918dfb251c1a63acdc07464b92.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8d5989c84e320b504511f23eeb6e7357.png)
再找出一组满足
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d1f9223bc24df8d429d743692fff7c06.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a13880b9454c5942f164d934b1834783.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/176400fc97133ee3a7bba932544318ea.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bb00b6918dfb251c1a63acdc07464b92.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8d5989c84e320b504511f23eeb6e7357.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76f0649064a085fb74c997fb507a9b6d.png)
乙同学:假设存在满足
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d1f9223bc24df8d429d743692fff7c06.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76f0649064a085fb74c997fb507a9b6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a13880b9454c5942f164d934b1834783.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/176400fc97133ee3a7bba932544318ea.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bb00b6918dfb251c1a63acdc07464b92.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8d5989c84e320b504511f23eeb6e7357.png)
再证明所有满足
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d1f9223bc24df8d429d743692fff7c06.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76f0649064a085fb74c997fb507a9b6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a13880b9454c5942f164d934b1834783.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/176400fc97133ee3a7bba932544318ea.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bb00b6918dfb251c1a63acdc07464b92.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8d5989c84e320b504511f23eeb6e7357.png)
丙同学:假设存在满足
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9dad69e399b3b4f68b777f6678c7ced7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76f0649064a085fb74c997fb507a9b6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a13880b9454c5942f164d934b1834783.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/176400fc97133ee3a7bba932544318ea.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bb00b6918dfb251c1a63acdc07464b92.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8d5989c84e320b504511f23eeb6e7357.png)
再证明所有满足
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9dad69e399b3b4f68b777f6678c7ced7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76f0649064a085fb74c997fb507a9b6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a13880b9454c5942f164d934b1834783.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/176400fc97133ee3a7bba932544318ea.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bb00b6918dfb251c1a63acdc07464b92.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8d5989c84e320b504511f23eeb6e7357.png)
A.只有甲同学的解题思路正确 | B.只有乙同学的解题思路正确 |
C.只有丙同学的解题思路正确 | D.有两位同学的解题思路都正确 |
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2022-10-14更新
|
111次组卷
|
2卷引用:上海市浦东复旦附中分校2022-2023学年高一上学期10月月考数学试题
名校
6 . 当用反证法证明命题“设
,
为实数,则关于
的方程
至少有一个实根”时,要做的假设是( )
![](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/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d101a3bf690228924d4ed0c4e3e34ed.png)
A.方程![]() | B.方程![]() |
C.方程![]() | D.方程![]() |
您最近一年使用:0次
2022-07-04更新
|
66次组卷
|
2卷引用:陕西省西安市第三中学2022-2023学年高二上学期10月月考数学试题
名校
7 . 用反证法证明命题“若
,则a,b中至少有一个不为0”成立时,假设正确的是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9a68dbd91d6de68b550a5745ecd461d9.png)
A.a,b中至少有一个为0 | B.a,b中至多有一个不为0 |
C.a,b都不为0 | D.a,b都为0 |
您最近一年使用:0次
2022-07-02更新
|
175次组卷
|
4卷引用:上海市建平中学2023届高三上学期9月月考数学试题
8 . 用反证法证明命题:“已知
、
是自然数,若
,则
、
中至少有一个小于2”,提出的假设应该是( )
![](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/a02c42eb76182a468ec8c3bbd6bc376e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c94bb12cee76221e13f9ef955b0aab1.png)
A.![]() ![]() | B.![]() ![]() |
C.![]() ![]() | D.![]() ![]() |
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2022-06-07更新
|
254次组卷
|
2卷引用:广西河池市2021-2022学年高二下学期八校第二次联考数学(理)试题
9 . 用反证法证明命题:“对于三个实数a、b、c,若
,则
或
”时,提出的假设正确的是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/098943e98ad321740f83f0bb67004598.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2958030ec9d7543dda1f529593a915e2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad5e009486af263893ca8290be72f258.png)
A.![]() ![]() | B.![]() ![]() |
C.![]() | D.![]() |
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2022-01-24更新
|
686次组卷
|
6卷引用:河南省邓州春雨国文学校2021-2022学年高二下学期第一次月考文科数学试题
名校
10 . 用反证法证明命题:“三角形的内角中至少有一个不大于60°”时,假设正确的是( )
A.假设三个内角都不大于60° |
B.假设三个内角至少有一个大于60° |
C.假设三个内角至多有两个大于60° |
D.假设三个内角都大于60° |
您最近一年使用:0次
2022-04-21更新
|
559次组卷
|
7卷引用:广西贺州第五高级中学2021-2022学年高二下学期第一次月考数学(理)试题