1 . 完成下面的证明.
,
,求证:
.
证明:∵
,
∴
(___________)
∵
,
∴___________
(__________).
∴
(__________).
(2)如图(2),点D、E、F分别是
的边
,
,
上的点,
,
.
求证:
.
证明:∵
,
∴
(___________)(___________)
∵
,
∴
(___________)(___________)
∴
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1bd5feafc07a9c84075810d1a44de3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e3379816bebb022875ea7f520d580e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/333ab24c4935210f4c232cd0c0fae358.png)
证明:∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1bd5feafc07a9c84075810d1a44de3d.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/764ed45a093a7c8c76dcc27937510f15.png)
∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e3379816bebb022875ea7f520d580e9.png)
∴___________
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fdcc4a27c785337e2135c07d111750ef.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/333ab24c4935210f4c232cd0c0fae358.png)
(2)如图(2),点D、E、F分别是
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9abaeba15f3abdd877bc701af52c5cd9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca14fa885a9d04f04e0418b49b118241.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/100b3e7dcd5f34c5234971cd75bff138.png)
求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a8124688c0c1330a37afac0d6996c45e.png)
证明:∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/64b8f1e9bd4cd5f311e5671500011344.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eb651ac2cf8469d28f85e608dc047d14.png)
∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e4fe71c95203f7a3717bb451beb0e7b1.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce2a8bf5e05a07c93a7104839fc21849.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a8124688c0c1330a37afac0d6996c45e.png)
您最近一年使用:0次
2024-05-12更新
|
88次组卷
|
3卷引用:黑龙江省龙东地区部分学校2023-2024学年七年级下学期期中数学试题
黑龙江省龙东地区部分学校2023-2024学年七年级下学期期中数学试题(已下线)黑龙江省佳木斯市桦南县2023-2024学年七年级下学期期中数学试题黑龙江省佳木斯市抚远市2023-2024学年七年级下学期期中数学试题
2 . 已知:如图,
平分
,
,求证:
.
平分
(已知)
_______
_______(__________________)
(已知)
_________(__________________)
(__________________)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdb8eca20ce2c918ea4034ea15210c7f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0e53497af8899cb299d762f1a4f46a55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b0fff774b4b0087a6f304ce930d359be.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dbc12dbfa29bc61b3f0d930f59f94458.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdb8eca20ce2c918ea4034ea15210c7f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54bb3caba2b157026325b3d8a5404fc8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9f617fa80f09fc245909492f5335ea5c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7c08980b6afedc04aa04f385791f0163.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6b8b514fa233dfa2dabd7ffb5f02e4e0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5e7e9d074ca70581092f0299b40813bd.png)
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名校
3 . 已知
中,
,求证:
,用反证法证明:第一步是:假设_____ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/047dc9795efa99b6fb9fdf9778085dab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/02ad4a810a0e043b67f3dfe44a0e9bbf.png)
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2024-03-30更新
|
50次组卷
|
4卷引用:宁夏中卫市第七中学2023-2024学年八年级下学期第一次月考数学试题
宁夏中卫市第七中学2023-2024学年八年级下学期第一次月考数学试题河南省驻马店市驿城区第二初级中学2023-2024学年八年级下学期期中数学试题河南省焦作市温县2023-2024学年八年级下学期4月期中考试数学试题(已下线)北师大八年级下学期期中必刷常考60题(37个考点专练)-2023-2024学年八年级数学下学期考试满分全攻略高频考点+重难点讲练与测试(北师大版)
4 . 完成下列证明.
已知:如图,
,
,求证:
证明:∵
(已知),
∴
___________( )
∵
(已知),
∴
___________( ),
∴
( )
已知:如图,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b0fff774b4b0087a6f304ce930d359be.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f54e848760cddfe1cd83bf799b4a3b42.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d730ae4307db56b47849c3a19dedfb3f.png)
证明:∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b0fff774b4b0087a6f304ce930d359be.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fbf9f8531e494afdf9215b7a3c589530.png)
∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f54e848760cddfe1cd83bf799b4a3b42.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fbf9f8531e494afdf9215b7a3c589530.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d730ae4307db56b47849c3a19dedfb3f.png)
您最近一年使用:0次
2024八年级下·全国·专题练习
5 . 用反证法证明命题“已知
中,
;求证:
.”第一步应先假设_______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e428e7a09732be85c1224e9c8f6a71c5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d89ba4036a5d18ec4abed44d7fd8e89.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/af79478474afadc824966a6bbf32af70.png)
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6 . 如图,
,
.求证:
.
证明:∵
,
∴
( ).
∵
,
∴
( ).
∴
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b0fff774b4b0087a6f304ce930d359be.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/173904239da66b7bef7cb1d997cc40ed.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b53df2a88f461611f7159d0f2f8ef60e.png)
证明:∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b0fff774b4b0087a6f304ce930d359be.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/afde09d82ae96f00c135732baee64776.png)
∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/173904239da66b7bef7cb1d997cc40ed.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4df89e372474c87ac158a7b8f22e27b8.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b53df2a88f461611f7159d0f2f8ef60e.png)
您最近一年使用:0次
7 . 小惠自编一题:“如图,在四边形
中,对角线
,
交于点O,
,
,求证:四边形
是菱形”,并将自己的证明过程与同学小洁交流.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cfc1f76257275ab4b04f9bc913535670.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0866e1551b61074ca8e61261ecd1f9dc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
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8 . 如图,直线
被直线l所截,
.求证:
.下面是某同学的证明过程,则①为 _________________ .
证明:
,
(对顶角相等).
,
.
(①).
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/62ff2912fd8d93b6e692936d95b727c5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/18ffab06cf944e7c4fd5a023e30aad9d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2bc8444d63d1ca92651c62fe9b220859.png)
证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3fb54630f3d069b83dc33de87e392ec9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3156eb5901beff24d22c730dd55add84.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e70839aab9ad65cc7298290a0abd75b6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/975cabbf0de47f488f3e2cf9d1f23cd9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/329a673b9019f8c73591b5c978bcdbb0.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/4/10/d419d85a-b304-4826-8683-07a755976ce5.png?resizew=140)
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9 . 如图所示,在
和
中,给出以下4个论断:
(1)
;
(2)
;
(3)
;
(4)
.
以其中三个论断为题设,填入下面的“已知”栏中,另一个论断为结论,填入下面的“求证”栏中,使之组成一个正确的命题,并写出证明过程.
已知:________;
求证:________.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e742966e3711cfa53dce04022acf4bcc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7ac451db3443cabb204f96c31fd4a02e.png)
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/047dc9795efa99b6fb9fdf9778085dab.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2d212c1709b8e72a055cf1b5381ef64.png)
(3)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/024dc2ccbbe321774df5d44e8785b203.png)
(4)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20004409a974fc56474e8dd8bc175d7b.png)
以其中三个论断为题设,填入下面的“已知”栏中,另一个论断为结论,填入下面的“求证”栏中,使之组成一个正确的命题,并写出证明过程.
已知:________;
求证:________.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/19/1748aac1-689f-42bd-84b9-88a213a7fe10.png?resizew=147)
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10 . 如图,已知
,且
.求证:
.请补充完成下列证明.
证明:∵
,
,
∴
(______).∴
(______).
∴
(______).又
(已知),
∴
(等量代换).
∴
(同位角相等,两直线平行).
∴
(______)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1d1717b5311ed602f1730e86d9322647.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d1598ad60d36f87f7fed1a58cf5c2c42.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bcae7985b857de84aa051b7267641005.png)
证明:∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1d1717b5311ed602f1730e86d9322647.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fa49b3773546351d07a85523ac52cb45.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/199599983f4c4affb2d83f7bd53dd79f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80e839f526856b5f54627427a2c1227c.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c3af5b69521f8ee7fb7fec50349677c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d1598ad60d36f87f7fed1a58cf5c2c42.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d615855728c32741778a138ba7627922.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0b8f65c8a0fdbf537cef53baa73b7cbe.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bcae7985b857de84aa051b7267641005.png)
您最近一年使用:0次