名校
1 . (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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名校
2 . 用反证法证明命题“设
,如果
能被5整除,那么
中至少有一个能被5整除”,假设应该是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4e248e4276d630c02ff008f332f4b3fc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/18f0281e6bbdbe08beeccb55adf84536.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/632244ea6931507f8656e1cc3437d392.png)
A.![]() | B.![]() |
C.![]() ![]() | D.![]() |
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解题方法
3 . (1)设
为实数,比较
与
的值的大小;
(2)设
.用反证法证明:若
是奇数,则
是奇数.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc997a4317a3b64369178b27abc44b95.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d5e738d349de57804c74596f26f8f200.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3b00438433719b82971f9fe309e04b5e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411a315870ed3e6d0e8ea885f1a04bcf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
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名校
4 . 用反证法证明命题“
或
”时要做的假设是________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bad3681a81aad62ffae694754859be41.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ff8411e793b5bb96a07e529a4883273.png)
您最近一年使用:0次
名校
5 . (1)
为实数,求证:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/04f25298d03745e6d91799449ed9e96a.png)
(2)用分析法证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76f0649064a085fb74c997fb507a9b6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/04f25298d03745e6d91799449ed9e96a.png)
(2)用分析法证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2b492c09f576ab6491af4848ce7ecec4.png)
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名校
6 . (1)设
,
是不全为零的实数,试比较
与
的大小.
(2)用反证法证明:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d053b14c8588eee2acbbe44fc37a6886.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bf877c2f179cf4e47657882ee8fa14d3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/00ecbb4dc189112b811b31483f2aa695.png)
(2)用反证法证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/557d2e3133709e7153c6177a52afc6e3.png)
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7 . 证明:
是无理数.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7ffe8515ff6183c1c7775dc6f94bdb8.png)
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8 . (1)设
,
,比较
与
的值的大小关系;
(2)已知
,
,
,其中
、
、
为实数,请用反证法证明:
、
、
中至少有一个为正数.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6b41d84627f6229005178c8b69d5d401.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c925be255ca736a53b24d13ddede1a86.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76d18e9ca603e7d02cf1788acdf105f2.png)
(2)已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/651b911b5b89924a9f1715d847e9d419.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76a130665c0842c5594882a282eab790.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0446cabe6eef4e5012d0bcf2be336f06.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/071a7e733d466949ac935b4b8ee8d183.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
您最近一年使用:0次
名校
9 . (1)已知
,用反证法证明:若
,则
中至少有一个小于
;
(2)已知
,判断 “
”是“
中至少有一个小于
”的什么条件?并说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f3eb9b6fe8959ae9e71e857b6d6fed49.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63381c4b8fb5ecfd04af2808a99dca46.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76f0649064a085fb74c997fb507a9b6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4dac452fbb5ef6dd653e7fbbef639484.png)
(2)已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f3eb9b6fe8959ae9e71e857b6d6fed49.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63381c4b8fb5ecfd04af2808a99dca46.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76f0649064a085fb74c997fb507a9b6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4dac452fbb5ef6dd653e7fbbef639484.png)
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10 . 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)
您最近一年使用:0次