名校
1 . 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)
您最近一年使用:0次
2023-03-10更新
|
252次组卷
|
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(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
名校
2 . 用数学归纳法证明“已知n为正奇数,求证:
能被
整除”时,第二步假设当
时命题为真后,需证![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f3cb8d72bb2e281b943b3b430138ef7.png)
________ 时命题也为真.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c41c0c0df2d1dd2b1f065f1df228ad81.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b88584cf1df43e28d03592c7998b1653.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f84335650257309409dc1bcc448aed41.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f3cb8d72bb2e281b943b3b430138ef7.png)
您最近一年使用:0次
名校
3 . 下列命题正确的有:________ .
①
;
②已知
,若
,则
.
③用反证法证明“已知
,且
,求证:
.”时,应假设“
且
”;
④命题“若
,则
”的逆否命题是“若
,则
”.
①
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/88d06a4bdf067ee8c14ce02d71271ddf.png)
②已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2dcbca3478eae63853d2aab5332e2e56.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eecb11de93939d81b65541b0bbdeb7f7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8efd32ba5030535598e979fd6d3a4d5c.png)
③用反证法证明“已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2dcbca3478eae63853d2aab5332e2e56.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c988d709ba8cd8aed6cb83d76c0ba89c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ea5977232839b54df456aeeacb13512d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/38f0e9c04402a0ffdaa25c3e3c82c7dd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1c412d5329ba909164329663b7eecdfe.png)
④命题“若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d1fdf7d28b97fb6fe731703f80e122ed.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b384412acba251d87902ab928902f16.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0e30c903d8f8a05332af0b19e7e40df3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9a8a2a94168af9b16ce89271a5d8dc6b.png)
您最近一年使用:0次
2021高二下·全国·专题练习
4 . 完成反证法证题的全过程.
题目:设a1,a2,
,a7是由数字1,2,
,7任意排成的一个数列.
求证:乘积p=(a1-1)(a2-2)
(a7-7)为偶数.
证明:假设p为奇数,则________ 均为奇数.①
因为7个奇数之和为奇数,故有
(a1-1)+(a2-2)+
+(a7-7)为________ .②
而(a1-1)+(a2-2)+
+(a7-7)
=(a1+a2+
+a7)-(1+2+
+7)=________ .③
②与③矛盾,故p为偶数.
题目:设a1,a2,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/daa5e9bd516f6282483b92cfe6074623.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/daa5e9bd516f6282483b92cfe6074623.png)
求证:乘积p=(a1-1)(a2-2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/daa5e9bd516f6282483b92cfe6074623.png)
证明:假设p为奇数,则
因为7个奇数之和为奇数,故有
(a1-1)+(a2-2)+
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/daa5e9bd516f6282483b92cfe6074623.png)
而(a1-1)+(a2-2)+
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/daa5e9bd516f6282483b92cfe6074623.png)
=(a1+a2+
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/daa5e9bd516f6282483b92cfe6074623.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/daa5e9bd516f6282483b92cfe6074623.png)
②与③矛盾,故p为偶数.
您最近一年使用:0次
解题方法
5 . 阅读下面题目及其证明过程,并回答问题.
如图,在三棱锥
中,
底面
,
,
,
分别是棱
,
的中点.
![](https://img.xkw.com/dksih/QBM/2020/11/10/2590155875131392/2590586443956224/STEM/59e96d8fb6364a7a9a0c2415e5ced222.png?resizew=229)
(1)求证:
平面
;
(2)求证:
.
解答:(1)证明:在
中,
因为
,
分别是
,
的中点,
所以
.
因为
平面
,
平面
,
所以
平面
.
(2)证明:在三棱锥
中,
因为
底面
,
平面
,
所以______.
因为
,且
,
所以______.
因为
平面
,
所以______.
由(1)知
,
所以
.
问题1:在(1)的证明过程中,证明的思路是先证______,再证______.
问题2:在(2)的证明过程中,设置了三个空格.请从下面给出的四个选项中,为每一个空格选择一个正确的选项,以补全证明过程.
①
;②
;③
平面
;④
.
如图,在三棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63397cda22cb1fad59cf966dfb588643.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/080db3af81b29ed10144a1c2e2a4fb8a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://img.xkw.com/dksih/QBM/2020/11/10/2590155875131392/2590586443956224/STEM/59e96d8fb6364a7a9a0c2415e5ced222.png?resizew=229)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57f9d682e5d3cc8573574d8d11636758.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e582d73b96ba649378379c3074d506d.png)
(2)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/58cc90fee532e50d319081d571410421.png)
解答:(1)证明:在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1c025ee3317be1099b7bf03a11e37ed4.png)
因为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
所以
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9f6c1984e2068203465b10ea4ead7916.png)
因为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/871502ee0c5d1414cfe81e8409b62d76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e582d73b96ba649378379c3074d506d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c9fe3c7e943c3beb7f4bbf345822064.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e582d73b96ba649378379c3074d506d.png)
所以
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57f9d682e5d3cc8573574d8d11636758.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e582d73b96ba649378379c3074d506d.png)
(2)证明:在三棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63397cda22cb1fad59cf966dfb588643.png)
因为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c8690d88536618e3f993dae41a3de66a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
所以______.
因为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/080db3af81b29ed10144a1c2e2a4fb8a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/34baf7aadc048e75e776b80eea5b62b5.png)
所以______.
因为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c9fe3c7e943c3beb7f4bbf345822064.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e582d73b96ba649378379c3074d506d.png)
所以______.
由(1)知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9f6c1984e2068203465b10ea4ead7916.png)
所以
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/58cc90fee532e50d319081d571410421.png)
问题1:在(1)的证明过程中,证明的思路是先证______,再证______.
问题2:在(2)的证明过程中,设置了三个空格.请从下面给出的四个选项中,为每一个空格选择一个正确的选项,以补全证明过程.
①
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a15a004f7d47ed595f063e60075223a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f0d9ef979b9f27a28cbda6923e888ccc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2ffc6952e988d04f22f0fb2f7f0ab7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e582d73b96ba649378379c3074d506d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/da48240e7fc3248f773ac1500c15ec14.png)
您最近一年使用:0次
2021高三·全国·专题练习
6 . 某同学准备用反证法证明如下一个问题:函数
在
上有意义,且
,如果对于不同的
、
,都有
,求证:
.那么他的反设应该是________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09f86f37ec8e15846bd731ab4fcdbacd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e11f4ca0e7ace69f92130d0525bcdb3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2aeb3ca8cbc4facb2467b1a618f33794.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c814128ea2139e33db94ea590e7c2223.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6a49684ba67f71171321586f1a77ad4a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/67e9d063f31e28b30e052bfbf7002663.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49a2b43fdce5aaae58c0907de23cbc6c.png)
您最近一年使用:0次
7 . 请根据所给的图形,把空白之处填写完整.
(1)直线与平面平行的性质定理(请用符号语言作答).
如图①,已知:a∥α,______ ,
求证:_____ .
(2)平面与平面垂直的性质定理的证明.
如图②,已知:α⊥β,AB∩CD=B,α∩β=CD,____ ,____ ,
求证:AB⊥β.
证明:在β内引直线____ ,垂足为B,则____ 是二面角____ 的平面角,
由α⊥β,知____ ,又AB⊥CD,BE和CD是β内的两条____ 直线,所以AB⊥β.
(1)直线与平面平行的性质定理(请用符号语言作答).
如图①,已知:a∥α,
求证:
(2)平面与平面垂直的性质定理的证明.
如图②,已知:α⊥β,AB∩CD=B,α∩β=CD,
求证:AB⊥β.
证明:在β内引直线
由α⊥β,知
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/25/aa46a720-1294-48a4-b049-f071de3c6ba7.png?resizew=266)
您最近一年使用:0次
名校
8 . 新教材人教B版必修第二册课后习题:“求证方程
只有一个解”.证明如下:“化为
,设
,则
在
上单调递减,且
,所以原方程只有一个解
”.解题思想是转化为函数.类比上述思想,不等式
的解集是__________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c18c032d75893db45e61e6c4eb0d4e4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49cfb1e9557770560280b5248ae2d0d8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/856491b01dab707170d83a1bc4b1f257.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09f86f37ec8e15846bd731ab4fcdbacd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4aa0df7f1e45f9de29e802c7f19a4f64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dec65a2bec3d4296c613a80b3ae41d5e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/707ea658f3a9359f5740d5aab48f7948.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5eb24655f40cd3200323b4f920c9f473.png)
您最近一年使用:0次
2020-11-04更新
|
706次组卷
|
7卷引用:湖北省黄冈市麻城一中2019-2020学年高三上学期期末数学(理)试题
湖北省黄冈市麻城一中2019-2020学年高三上学期期末数学(理)试题辽宁省抚顺市二中、旅顺中学2019-2020年高三上学期期末考试数学试题辽宁省辽南协作体2019-2020学年高三上学期期末考试数学文试题辽宁省辽南协作体2019-2020学年高三上学期期末考试数学理试题安徽省六安市舒城中学2020-2021学年高二下学期开学考试数学(理)试题(已下线)第18讲 数学思想选讲(二)-【提高班精讲课】2021-2022学年高一数学重点专题18讲(沪教版2020必修第一册,上海专用)内蒙古海拉尔第二中学2021-2022学年高三上学期第一次阶段考数学(文科)试题
名校
9 . 用反证法证明“设
,求证
”时,第一步的假设是______________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/127a0d8c1c7d15ed40ec4b8bca0ebdf6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/485a2d99320384a0857b00ce9ab9e990.png)
您最近一年使用:0次
2020-03-20更新
|
474次组卷
|
7卷引用:江苏省连云港市锦屏高级中学2017-2018学年高二下学期期中数学(理)试题
名校
10 . 设
,
,
,…,
,希望证明
,在应用数学归纳法求证上式时,第二步从
到
应添的项是______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5d7d41cdc17d1d73868a0eafb5621a2e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f395576519def6a4df88b8fa4e524767.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c0598b97e0d061dd458626a080bd1ec6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8be7b032a433583d2414f9f504b8630.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ff0ad23f8781ebb49107aa5dbf5fa9fc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f0a532e15e232cb4b99a8d4d07c89575.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1b00f4eb7f1bd2ccefbabf0c1dfa8f69.png)
您最近一年使用:0次
2020-01-30更新
|
234次组卷
|
2卷引用:上海市上海外国语大学附属外国语学校2017-2018学年高二上学期期中数学试题