如图,
,BE平分∠ABC,CE平分∠BCD,若E在AD上.
求证: E为AD的中点.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/10df84d553a8826a7ce9bff4bf0d95b9.png)
求证: E为AD的中点.
![](https://img.xkw.com/dksih/QBM/2020/11/17/2595043476398080/2595152363446272/STEM/f75548348fe34a9d9dcb526c5395f4d2.png?resizew=164)
更新时间:2020-11-17 23:13:54
|
相似题推荐
解答题-证明题
|
较难
(0.4)
【推荐1】如图,已知∠AOB=120°,在∠AOB的平分线OM上有一点C,将一个60°角的顶点与点C重合,它的两条边分别与直线OA、OB相交于点D、E.
(1)当∠DCE绕点C旋转到CD与OA垂直时(如图1),请猜想OE+OD与OC的数量关系,并说明理由;
(2)当∠DCE绕点C旋转到CD与OA不垂直时,到达图2的位置,(1)中的结论是否成立?并说明理由;
(3)当∠DCE绕点C旋转到CD与OA的反向延长线相交时,上述结论是否成立?若成立,请给于证明;若不成立,线段OD、OE与OC之间又有怎样的数量关系?请写出你的猜想,不需证明.
(1)当∠DCE绕点C旋转到CD与OA垂直时(如图1),请猜想OE+OD与OC的数量关系,并说明理由;
(2)当∠DCE绕点C旋转到CD与OA不垂直时,到达图2的位置,(1)中的结论是否成立?并说明理由;
(3)当∠DCE绕点C旋转到CD与OA的反向延长线相交时,上述结论是否成立?若成立,请给于证明;若不成立,线段OD、OE与OC之间又有怎样的数量关系?请写出你的猜想,不需证明.
![](https://img.xkw.com/dksih/QBM/2018/11/15/2075969447723008/2082943169167360/STEM/1905378b2a03406ea8512823c621528d.png?resizew=472)
您最近一年使用:0次
解答题-证明题
|
较难
(0.4)
【推荐2】已知AB
CD,点E是平面内一点,∠CDE的角平分线与∠ABE的角平分线交于点F.
(1)若点E的位置如图1所示.
①若∠ABE=60°,∠CDE=80°,则∠F= °;
②探究∠F与∠BED的数量关系并证明你的结论;
(2)若点E的位置如图2所示,∠F与∠BED满足的数量关系式是 .
(3)若点E的位置如图3所示,∠CDE 为锐角,且
,设∠F=α,则α的取值范围为 .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fb31ef428bd9de9bc875b343feded3c7.png)
(1)若点E的位置如图1所示.
①若∠ABE=60°,∠CDE=80°,则∠F= °;
②探究∠F与∠BED的数量关系并证明你的结论;
(2)若点E的位置如图2所示,∠F与∠BED满足的数量关系式是 .
(3)若点E的位置如图3所示,∠CDE 为锐角,且
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96ab12e7d7e0a40d5d5e05df1e1e9c9e.png)
![](https://img.xkw.com/dksih/QBM/2020/8/15/2528599112613888/2531190871670784/STEM/1e7c7f285c61470ba9e958f1800d6f76.png?resizew=519)
您最近一年使用:0次
解答题-证明题
|
较难
(0.4)
解题方法
【推荐1】如图,直线
与直线
分别交于点
与
互补.
![](https://img.xkw.com/dksih/QBM/2020/5/8/2458322121924608/2458948456357888/STEM/c63a1a27-7714-4149-9ab1-b9fe9318fb99.png)
(1)如图1.求证:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8decd68a7b56b0e4ef636e11b1937e12.png)
(2)如图1,
的角平分线交于点
与
交于点
,点
是
上一点,且
,求证:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e5fba3dce19dd568b7a09481825c57ad.png)
(3)如图2,在(2)的条件下,连接
是
上一点使
,作
平分
,问
的大小是否发生变化?若不变,请求出其值,若变化,说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b10ff911ab3353e9b8221d258d4112ab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/494a85bac4c48746db5513ba03db8d2e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/05cbf5c2be437d5794e83deca8a53e7a.png)
![](https://img.xkw.com/dksih/QBM/2020/5/8/2458322121924608/2458948456357888/STEM/c63a1a27-7714-4149-9ab1-b9fe9318fb99.png)
(1)如图1.求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8decd68a7b56b0e4ef636e11b1937e12.png)
(2)如图1,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e10d16821f5bc5a31b4a6fc3da8f0e2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd585ed4ee273f8d085e12ccd5fad0c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73465a1f9aa03481295bf6bd3c6903ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1cb1de78a83c3a206ed3a3949e313f4e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e5fba3dce19dd568b7a09481825c57ad.png)
(3)如图2,在(2)的条件下,连接
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4a56b43d0cd210388cfa8e125d4ee3ea.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e42887d9bf31c1dd99f13c39e63c9ab9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c5eddb6d5a5df354aa489c3e10b307b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a5f1641947153c80b987320885a2b57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e00216eb8b0f3b8c1e0713c98fa4dc5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dce75683961a8db6056e9b478647926b.png)
您最近一年使用:0次
解答题-问答题
|
较难
(0.4)
【推荐2】如图,已知直线AB∥CD,直线L和直线AB,CD分别交于点E,F,直线L上有一动点P.
![](https://img.xkw.com/dksih/QBM/2020/4/17/2443192296906752/2443412849745920/STEM/7bcebbf5d54e459dacad8d9bfca3dfbf.png?resizew=491)
(1)如图1,点P在E,F之间运动时,∠PMB,∠MPN,∠PND之间有什么关系,并说明理由;
(2)若点P在E,F两点外侧运动时,如图2和图3(P点与E,F不重合),试直接写出∠PMB,∠MPN,∠PND之间有什么关系,不必写理由.
![](https://img.xkw.com/dksih/QBM/2020/4/17/2443192296906752/2443412849745920/STEM/7bcebbf5d54e459dacad8d9bfca3dfbf.png?resizew=491)
(1)如图1,点P在E,F之间运动时,∠PMB,∠MPN,∠PND之间有什么关系,并说明理由;
(2)若点P在E,F两点外侧运动时,如图2和图3(P点与E,F不重合),试直接写出∠PMB,∠MPN,∠PND之间有什么关系,不必写理由.
您最近一年使用:0次
解答题-证明题
|
较难
(0.4)
【推荐1】如图1,在平面直角坐标系中,A(a,0),B(0,b),且a、b(其中
)是方程
的两个根.
![](https://img.xkw.com/dksih/QBM/2022/4/24/2965098460291072/3029001391874048/STEM/ed5e43ce309640c4b064a99559291b50.png?resizew=625)
(1)求直线
的解析式;
(2)若点
为直线
在第一象限上一点,当以
为直角边
ABM是等腰直角三角形时,求m的值;
(3)如图3,过点
的直线
交y轴负半轴于点
,
点的横坐标为
,过
点的直线
交
于点
,给出两个结论:①
的值是不变;②
的值是不变,只有一个结论是正确,请你判断出正确的结论,并加以证明和求出其值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c6a46e678bf9d2df5ad4c782b3dc22f5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca0a5f96778e7c10c34870076e9c5c49.png)
![](https://img.xkw.com/dksih/QBM/2022/4/24/2965098460291072/3029001391874048/STEM/ed5e43ce309640c4b064a99559291b50.png?resizew=625)
(1)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
(2)若点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5cca39b30b0b8e769293e13546b91f35.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce4cba95fc7d4853a243f8e3fb20ce70.png)
(3)如图3,过点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9212d499bc3042676d7fe366e3f1cf5b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acbc6a613224461ade69362d46550474.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b550678481b54cf5bbfd92c7795df761.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20a541b81584a032f571159ea152c85a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c63b92431fec14cb79c0e08e88a0ea9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4d4f1b292e10aafdc8dc9c205079b30c.png)
您最近一年使用:0次
解答题-证明题
|
较难
(0.4)
【推荐2】在一节数学课上,张老师提出了这样一个问题:“如图1,在等腰直角三角形
中,
,D是边
上一动点(不与B重合),
,
交
于点F.猜想线段
,
之间的数量关系并说明理由.”小聪和同桌小明讨论后,仍不得其解.张老师给出提示:数学中常通过把一个问题特殊化来找到解题思路.两个人茅塞顿开,于是进行了如下讨论,请仔细阅读,并完成相应的任务.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/2/27/07c13ed6-12b8-4e17-8261-2e2c0d6108be.png?resizew=184)
小聪:己知点D是动点,因此可以将点D移动到一个特殊的位置.当点D与点C重合时,如图2所示.此时可以分别延长
,
交于点H,如图3所示,可证明
,进而得出线段
,
之间的数量关系.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/2/27/38ea3bc3-c904-4bab-a184-2de43bd6cc33.png?resizew=531)
小明:对于图2,过点F分别作
,
的平行线,交边
于点M,N,如图4所示,可证明
,进而得出线段
,
之间的数量关系.
(1)任务一:
如图2,判断线段
,
之间的数量关系:并在小聪与小明的方法中选择一种,写出详细的证明过程.
(2)任务二:
如图1,请直接猜想
,
之间的数量关系为__________.
(3)任务三:
如图1,若
,当
是直角三角形时,直接写出
的长(用含a的代数式表示).
![](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/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e442482a0fcf9142018bdfdbc6afa094.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d004d2d115b477ade6af7ddb93db0df8.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/2/27/07c13ed6-12b8-4e17-8261-2e2c0d6108be.png?resizew=184)
图1
小聪:己知点D是动点,因此可以将点D移动到一个特殊的位置.当点D与点C重合时,如图2所示.此时可以分别延长
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9abaeba15f3abdd877bc701af52c5cd9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1403c36beeb944930e94dfa4520360ce.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d004d2d115b477ade6af7ddb93db0df8.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/2/27/38ea3bc3-c904-4bab-a184-2de43bd6cc33.png?resizew=531)
图2 图3 图4
小明:对于图2,过点F分别作
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6c7ad2b1fe347c9f98c0f5086f6e59a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d004d2d115b477ade6af7ddb93db0df8.png)
(1)任务一:
如图2,判断线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d004d2d115b477ade6af7ddb93db0df8.png)
(2)任务二:
如图1,请直接猜想
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d004d2d115b477ade6af7ddb93db0df8.png)
(3)任务三:
如图1,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6d42e97eee705d164e6ac6de9ecd6d1f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/441dec590b47adc3678a291a3ec89a4a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
您最近一年使用:0次
解答题-证明题
|
较难
(0.4)
【推荐1】已知,在
中,
,
,
,垂足为点
,且
,连接
.
(1)如图①,求证:
是等边三角形;
(2)如图①,若点
、
分别为
,
上的点,且
,求证:
;
(3)利用(1)(2)中的结论,思考并解答:如图②,
为
上一点,连结
,当
时,线段
,
,
之间有何数量关系,给出证明.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0faed94a64b2dcfc6801b4fca0f16675.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0fffa3d9c32da53b0ea0c338012ea20c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/047dc9795efa99b6fb9fdf9778085dab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b5f215a42c4b7078d8d65923eb9980e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f2ddd49625097d0a78df7170be4f882e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
(1)如图①,求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/db5e1441a49e782ff0ef46e776cde06a.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/10/26/5cb5e507-4738-4a52-920a-844dcbce34eb.png?resizew=173)
(2)如图①,若点
![](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/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9f3bba5bd11e850c9b766c2ba6c426d1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/97075fe3c2a105f5d2d0a27a9f2b3410.png)
(3)利用(1)(2)中的结论,思考并解答:如图②,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73465a1f9aa03481295bf6bd3c6903ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c7e4fa04825ac7d071968056322d88be.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/282e9e4a6dd9899bcb52a48864e263ce.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bcdae78f4d3b8d8213ac3ac9a9567eb5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/53b95463a97c60db3250cb641bf6523d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/10/26/5a61feb2-d49f-40d6-8c09-f2f4537e574e.png?resizew=179)
您最近一年使用:0次
解答题-证明题
|
较难
(0.4)
名校
【推荐2】如图,在
中
,以
为直径的
与
交于点D,过点D作
的切线交
于点E.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/31/203df13c-1745-45c2-b21c-d4404b2748ab.png?resizew=182)
(1)求证:
;
(2)若
的半径为
,
,求
的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b3c65edad25ddd666cdce0d7e5afefc9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/047dc9795efa99b6fb9fdf9778085dab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/31/203df13c-1745-45c2-b21c-d4404b2748ab.png?resizew=182)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8d75ce112dc24a65d61b5e2094f0f2a6.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/700762875cb4f15b556a72f10a42ac9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d0d5a2cd05e4476fc72271e8fdb59a9a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
您最近一年使用:0次