用反证法证明命题“已知
.如果
,那么a,b都不为0”时,假设的内容应为( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/360ff131c51a4ef6745538c18cec92c2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9eae9ba258299eb489b490594397e23c.png)
A.a,b都为0 | B.a,b不都为0 | C.a,b中至少有一个为0 | D.a不为0 |
更新时间:2021-08-15 15:25:24
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【推荐1】用反证法证明“
,如果
、
能被2017整除,那么
中至少有一个能被2017整除”时,假设的内容是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8ef95f8f15ff735ec3128ad20abdf04e.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/632244ea6931507f8656e1cc3437d392.png)
A.![]() | B.![]() |
C.![]() | D.![]() |
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单选题
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较易
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【推荐2】用反证法证明命题:“一个三角形中不能有两个直角”的过程归纳以下三个步骤:
①
,这与三角形内角和为180°相矛盾,
不成立;
②所以一个三角形不能有两个直角;
③假设三角形的三个内角
,
,
中有两个直角,不妨设
;
正确顺序的序号为
①
![](https://img.xkw.com/dksih/QBM/2017/5/1/1677586164473856/1678579004547072/STEM/6099c9cb77b34dee9727cc7f2b883da7.png?resizew=140)
![](https://img.xkw.com/dksih/QBM/2017/5/1/1677586164473856/1678579004547072/STEM/add0898eebfd4fcd80ccd8076437bd1f.png?resizew=72)
![](https://img.xkw.com/dksih/QBM/2017/5/1/1677586164473856/1678579004547072/STEM/2ee94680ff604ab5a7fc921d3f439c0a.png?resizew=80)
②所以一个三角形不能有两个直角;
③假设三角形的三个内角
![](https://img.xkw.com/dksih/QBM/2017/5/1/1677586164473856/1678579004547072/STEM/08e555acbdee4f959ad68b865e4031d3.png?resizew=16)
![](https://img.xkw.com/dksih/QBM/2017/5/1/1677586164473856/1678579004547072/STEM/cd10ddb76ed347299ea35ae46177bfa0.png?resizew=16)
![](https://img.xkw.com/dksih/QBM/2017/5/1/1677586164473856/1678579004547072/STEM/8b41098b6d72429baf1fb5f33da60b4b.png?resizew=16)
![](https://img.xkw.com/dksih/QBM/2017/5/1/1677586164473856/1678579004547072/STEM/2ee94680ff604ab5a7fc921d3f439c0a.png?resizew=80)
正确顺序的序号为
A.①②③ | B.③①② | C.①③② | D.②③ |
您最近一年使用:0次