解题方法
1 . 阅读下面题目及其证明过程,在
处填写适当的内容.
已知三棱柱
,
平面
,
,
分别为
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/27/daabe3a8-f5d5-4b94-9577-eeb61c3f5b0f.png?resizew=135)
(1)求证:
∥平面
;
(2)求证:
⊥
.
解答:(1)证明: 在
中,
因为
分别为
的中点,
所以 ① .
因为
平面
,
平面
,
所以
∥平面
.
(2)证明:因为
平面
,
平面
,
所以 ② .
因为
,
所以
.
又因为
,
所以 ③ .
因为
平面
,
所以
.
上述证明过程中,第(1)问的证明思路是先证“线线平行”,再证“线面平行”; 第(2)问的证明思路是先证 ④ ,再证 ⑤ ,最后证“线线垂直”.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80d5d02301554aad6cc89452c83f0862.png)
已知三棱柱
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5845ccc0d735dc14c92a8926d9b1def6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c06154cae3bf7a8ce5a1e97a7380875.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad056c25c0fdcbcc765eb5cbc6093f2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/62d77afb7d8280995886ff690e7a6c9a.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/27/daabe3a8-f5d5-4b94-9577-eeb61c3f5b0f.png?resizew=135)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
(2)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ee8456443402a25b1e25d35ff7e1c98.png)
解答:(1)证明: 在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8f9e1e0d29bc4bdf0c6d38ca4db43343.png)
因为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad056c25c0fdcbcc765eb5cbc6093f2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/62d77afb7d8280995886ff690e7a6c9a.png)
所以 ① .
因为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/871502ee0c5d1414cfe81e8409b62d76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f196748dc6a0d0bd9e9e4dd30ac4ed0e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
所以
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
(2)证明:因为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5845ccc0d735dc14c92a8926d9b1def6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be509ef5101aae24609ff9941cb246fc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
所以 ② .
因为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c06154cae3bf7a8ce5a1e97a7380875.png)
所以
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36c4559d27e3905980d1a4f1856f07de.png)
又因为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e5d970e34169fb0de8a3f10e4c6ae40d.png)
所以 ③ .
因为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f6cb3896ef1afc6a56a5aa0243022e0d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6ac61c24f99a4e466f1e2ea011893866.png)
所以
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ba985fb50a9078a839b66bf1d1eadea9.png)
上述证明过程中,第(1)问的证明思路是先证“线线平行”,再证“线面平行”; 第(2)问的证明思路是先证 ④ ,再证 ⑤ ,最后证“线线垂直”.
您最近一年使用:0次
解题方法
2 . 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)
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名校
3 . 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)
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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理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
4 . 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)
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名校
5 . 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)
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2020-03-20更新
|
475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
6 . 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)
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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
7 . 分析法又称执果索因法,若用分析法证明:“设a>b>c,且a+b+c=0,求证
<
a”索的因应是_______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a69176dcecef776dd3e89f5f8955cf60.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7ffe8515ff6183c1c7775dc6f94bdb8.png)
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8 . 分析法又称执果索因法.若用分析法证明“设
,且
,求证:
”索的因应是______ .
①
;②
;③
;④
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce613eaa5df46a50174085ef5d1087fb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e56f4504e0f80fd031c8b5f41832e03.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bff6d61a8eaff20b364a9e3235577c69.png)
①
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/481ee0d1e39e92a4732eea90225eb94c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d6e90787c63ca5b5f1a45e0f6e85aaa1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d8062c16e427bcf70b7ab5c94e8f25a1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e40e5c797b097deb1f9e89bcb3a405f1.png)
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解题方法
9 . 如图,在正方体
中,
是
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/4/6c0d410b-9639-4583-88dd-cf29de37c0da.png?resizew=176)
(1)求证:
平面
;
(2)求证:平面
平面
.(只需在下面横线上填写给出的如下结论的序号 :①
平面
,②
平面
,③
,④
,⑤
)
证明:(1)设
,连接
.因为底面
是正方形,所以
为
的中点,又
是
的中点,所以_________.因为
平面
,____________,所以
平面
.
(2)因为
平面
平面
,所以___________,因为底面
是正方形,所以_______,又因为
平面
平面
,所以_________.又
平面
,所以平面
平面
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/22adbc0da438220f9cace11b629d799b.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/4/6c0d410b-9639-4583-88dd-cf29de37c0da.png?resizew=176)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f11f1840eb8b17e7b07c3fe7e987a9c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca48c18021e7be4bbb3e95576e1c1b5f.png)
(2)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/077dcbb7a11d1ab7c9644bd1fe9b4368.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca48c18021e7be4bbb3e95576e1c1b5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e56fdf217165748fafe938b64fa08179.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cc78a86b12ba0b4553135a3a635fc418.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cffb30e92f06a10b82da994fa304d2c5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca48c18021e7be4bbb3e95576e1c1b5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0d7af0ab753d5017928560ae47de106.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/70734a8e672376bb0bd1522e229f86a2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/105cdc325328b683456c1443f6296f8b.png)
证明:(1)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a23f01af749100e1888bba06268843db.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f90c780dac29ff8b7df5881d3b33abab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7d97dc3b752832906de41447bb58a341.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/22adbc0da438220f9cace11b629d799b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1b2104bb78c7d7d58c1f51a25daa8086.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca48c18021e7be4bbb3e95576e1c1b5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f11f1840eb8b17e7b07c3fe7e987a9c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca48c18021e7be4bbb3e95576e1c1b5f.png)
(2)因为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ddbb0422a136f45653c8c369f2d75fc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9263a4c1054ec924e900a1544180a83b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/22bc82cd42e79c932abe14fa79265ed3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a03f5a663501d8fa265fdb593ed4bfab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cc78a86b12ba0b4553135a3a635fc418.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f196748dc6a0d0bd9e9e4dd30ac4ed0e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca48c18021e7be4bbb3e95576e1c1b5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/077dcbb7a11d1ab7c9644bd1fe9b4368.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca48c18021e7be4bbb3e95576e1c1b5f.png)
您最近一年使用:0次
名校
10 . 已知
,求证
的两根的绝对值都小于1,用反证法证明可假设__________
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7b8cfed3e48c308e325045cb87d7bdbb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1146110d4382c714c10de00dd1273b7f.png)
您最近一年使用:0次