1 . 四个人做一道选项为
的选择题,四个同学对话如下:
赵:我选
;钱:我选
当中的一个;孙:我选
;李:我选
;
四个人每人选了一个选项,而且各不相同,其中只有一个人说谎,则说谎的人可能是谁?( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf38f43d820c85fc06020c81bb45c00f.png)
赵:我选
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/525523273b64758484e178d4359d4d59.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f015ed8e497b4394053ddd19683a98f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7909220d1db380634534190b662ee0a7.png)
四个人每人选了一个选项,而且各不相同,其中只有一个人说谎,则说谎的人可能是谁?( )
A.赵,钱 | B.钱,孙 | C.孙,李 | D.李,赵 |
您最近一年使用:0次
2022-05-28更新
|
379次组卷
|
4卷引用:内蒙古呼伦贝尔市满洲里市2022届高三三模数学(文)试题
名校
2 . (1)用文字语言和符号语言叙述异面直线判定定理:
文字语言:过______一点和______一点的直线,和此平面上______的任何一条直线是异面直线;
符号语言:若______,则直线
与直线
异面.
(2)用反证法证明异面直线判定定理.
文字语言:过______一点和______一点的直线,和此平面上______的任何一条直线是异面直线;
符号语言:若______,则直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
(2)用反证法证明异面直线判定定理.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/17/0b755a73-3352-4334-8e98-4098033dc32d.png?resizew=137)
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3 . 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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解题方法
4 . 在解决问题:“证明数集
没有最小数”时可用反证法证明:
假设
是
中的最小数,则存在
,
可得:
,与假设中“a是A中的最小数”矛盾,
所以数集
没有最小数.
那么对于问题:“证明数集![](https://staticzujuan.xkw.com/quesimg/Upload/formula/148c4902eb8e6a73046dedab761e3abf.png)
,并且
没有最大数”,也可以用反证法证明:我们可以假设
是
中的最大数,则存在
,且
,其中
的一个值可以是__________ (用
、
表示),由此可知,与假设
是
中的最大数矛盾.所以数集
没有最大数.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/79950aacd93566f38d8e16021d2eb23b.png)
假设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/abc7dff3ffdad01a473cc8bdb236f2d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0914b68f106a912420705b2f3928ca42.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a2710435ef4f66f24a0f4b67d7e83f0e.png)
可得:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54bfb810e811cb3d9482e2ec0d8db742.png)
所以数集
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/79950aacd93566f38d8e16021d2eb23b.png)
那么对于问题:“证明数集
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/148c4902eb8e6a73046dedab761e3abf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eb45566dd4ac7dd3524acdb890c29bb6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f313d192b9d871f1e543f8ac1209b0a9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1ad6060180ef1fa5784a087be85d1f91.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1da9dcf6c319174c9ea2b1ceaed1649a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11a25178d007036b7fbde4ab793c98c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4cfc6ee6f3b4da7817d30e1b9dc36d2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bff1301d5d66379471b648952aea6310.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/26e93d8fb77f5bd2c0fc690752dfd771.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4d7e9f86738335a22298559db41037a4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1ad6060180ef1fa5784a087be85d1f91.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1da9dcf6c319174c9ea2b1ceaed1649a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1da9dcf6c319174c9ea2b1ceaed1649a.png)
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2022-10-26更新
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181次组卷
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2卷引用:上海市进才中学2022-2023学年高一上学期10月月考数学试题
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5 . 已知实数p满足不等式
,用反证法证明:关于x的方程
无实数根.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63677dc1c787631f6d59899c20e4a218.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/460717532e94a6abe9ea0e7c74bf87fb.png)
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20-21高一·全国·课后作业
解题方法
6 . 求证:如果两个平行平面同时与第三个平面相交,那么它们的交线平行(根据如图写出已知、求证并加以证明).
![](https://img.xkw.com/dksih/QBM/2021/4/17/2701599047794688/2703433862283264/STEM/29ecd1acba9745c4b826f63b88862ee6.png?resizew=175)
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解题方法
7 . 下列不等式判断正确的有( )
(1)
;
(2)
;
(3)若
,则
;
(4)若
,则
;
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4f012723166468ee405091aff20a6c05.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e392473aa00fae75dc92c2ccb697a0cd.png)
(3)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b9b419e7d63d2eee9c23c393210dfa6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/432d77fe5ad3032d59a237dd94c8a638.png)
(4)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/33e15c8237494322d425cedcb29b5e9c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/432d77fe5ad3032d59a237dd94c8a638.png)
A.(1)(3) | B.(2)(3) |
C.(2)(4) | D.(2)(3)(4) |
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8 . 已知
.
(1)若
,
,证明
为锐角三角形;
(2)如图,过顶点
作
,垂足
位于边
上.若
且
,证明
不是直角.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a32841dea3e0f06078e09450d29dbfac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/994eeb7944c572291623825627af7ea2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
(2)如图,过顶点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b757f0c42ae5c9a2d6a4b19e5877b27.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bacfdde1c91d4404be2fdf515a03437d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/55c24a968c73e960698a572ab01e3698.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8fabb884dc5f9609de491245463bbe9a.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/15/f9272433-89e2-4fe7-9df7-e62ab88224ad.png?resizew=168)
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9 . 已知
,
,
,用反证法证明“
与
至少有一个不小于3”的假设是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/94440d3e4c073f94f2b266ff99d50e74.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/67ca5fd57c2c2fcc3c7a574fdd1467d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5be97cd1c7111b654d87d8fbb63b6a84.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bc8ee230708950226bacead117cdbf6e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/393442926e96fddbce94ab3aeca809d3.png)
A.![]() ![]() | B.![]() ![]() |
C.![]() ![]() | D.![]() ![]() |
您最近一年使用:0次
20-21高一·全国·课后作业
10 . 证明:如果存在不全为0的实数s,t,使得
,那么
与
是共线向量;如果
与
不共线,且
,那么
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b453d6b4af8c8bf284ecd34deb2e5603.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb80eb942aafb194fadc473776f35b1d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/433b94c39737727e53468df419d8314a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb80eb942aafb194fadc473776f35b1d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/433b94c39737727e53468df419d8314a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b453d6b4af8c8bf284ecd34deb2e5603.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5deeb332fc7b636fbfb35be5d7f49622.png)
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