在
和
中,
,
,
,
与
相交于点
.
,延长
交
于点
,试判断
是否成立,并说明理由;
(2)如图2,若
,连接
.
①求证:
;
②延长
交
于点
,连接
.若
,求证:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a25c28359f8d8da9eaf4672a6cf8ae4f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/047dc9795efa99b6fb9fdf9778085dab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2d212c1709b8e72a055cf1b5381ef64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d959ad0bf10a92c6c6be067f7094fcb8.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/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c2f12c8e863e2661cb4a4b4138b06101.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be30dbd3acf3409d0b053989280f6c40.png)
(2)如图2,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/01e94dacf9ef98c98de9344a77079cf5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
①求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ec743b36b3ec1ae54db20df1ef7af82a.png)
②延长
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf3834d7ec7531f3c3c0ce9b286f7a49.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83ebffbdca89cc68c33706ab069fc6fb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/75250609e2c033ea6642aa786139d653.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b84903a6366284d1e180329d3fff0011.png)
更新时间:2024-05-22 16:03:12
|
相似题推荐
解答题-证明题
|
较难
(0.4)
【推荐1】如图
、
,在平行四边形
中,
、
的角平分线
、
分别与线段
两侧的延长线(或线段
)相交于
、
,
与
相交于点
.
![](https://img.xkw.com/dksih/QBM/2019/9/19/2293967128510464/2294280072634368/STEM/79cabcb8aaf0485d9dd40ddc4feacc61.png?resizew=216)
![](https://img.xkw.com/dksih/QBM/2019/9/19/2293967128510464/2294280072634368/STEM/e5d689ecf1cd4c96ba399001f44cb3ab.png?resizew=203)
(1)在图
中,求证:
,
.
(2)在图
中,仍有(1)中的
,
成立,请解答下面问题:
①若
,
,
,求
和
的长;
②是否能给平行四边形
的边和角各添加一个条件,使得点
恰好落在
边上且
为等腰三角形?若能,请写出所给条件;若不能,请说明理由.
![](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/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2947ca8e0cdbeb4aab80ce9e7b63ba98.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d39b8d91afc34e4a9b0fdbb6bafb9087.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/06e322e0c87479bba874db9ae9ba36b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/06e322e0c87479bba874db9ae9ba36b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://img.xkw.com/dksih/QBM/2019/9/19/2293967128510464/2294280072634368/STEM/79cabcb8aaf0485d9dd40ddc4feacc61.png?resizew=216)
![](https://img.xkw.com/dksih/QBM/2019/9/19/2293967128510464/2294280072634368/STEM/e5d689ecf1cd4c96ba399001f44cb3ab.png?resizew=203)
(1)在图
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5c627c657d0139d1c7cc99ddb83f1a09.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/baedb038db26d9c599cdd2414695d772.png)
(2)在图
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c94bb12cee76221e13f9ef955b0aab1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5c627c657d0139d1c7cc99ddb83f1a09.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/baedb038db26d9c599cdd2414695d772.png)
①若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc34db5860990e51ba31edc8cdd077c2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/267ace52b64e1e7dfc5211e033255b7d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61d3bb5ccfeb2c7dd034915958ec40c6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c63e36329f5e0979f5ee776ac5d06327.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
②是否能给平行四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cc3814287dbb60d478bffc5366f9928b.png)
您最近一年使用:0次
解答题-作图题
|
较难
(0.4)
【推荐2】如图,
,P为线段
上的一点.
(1)在图①中仅用圆规和无刻度直尺分别在
、
上分别作点E、F,使
,且
.无需写出作图步骤,但保留作图痕迹;
(2)若
,求
.(图②供问题(2)用)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/75352b13ae09502e8368e16ecbe990f9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/9/8abb53d9-be10-4a97-80d6-97cdd8fad1f3.png?resizew=385)
(1)在图①中仅用圆规和无刻度直尺分别在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ddde70e202864dc56af2022e944b73f3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4467bd49c79c380a775cc802086050ec.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ada3f458d33488909c851ff39ca72c57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7be0adab3ae7852d1eb59777cf96ec71.png)
您最近一年使用:0次
解答题-证明题
|
较难
(0.4)
【推荐1】在
中,点D、E分别在
、
边上,设
与
相交于点F.如图,设
,
,点G在
的延长线上,连接
、
;若
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/11/21/59e53116-2906-4105-9408-235b93174b21.png?resizew=150)
(1)求证:
;
(2)证明:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.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/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d320f180419175d75eebc618cc458b39.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b757f0c42ae5c9a2d6a4b19e5877b27.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/77a7e4a6765ce78b05ee97764771e01f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/14a50461bb92ca6a5495c22898a3ff8e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/66ade1f23962d19c1fabc48d0c26e016.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/11/21/59e53116-2906-4105-9408-235b93174b21.png?resizew=150)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c29783305ab70b6179f2f58714454f74.png)
(2)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b24ab72f35aafdad5484127ee96da699.png)
您最近一年使用:0次
解答题-证明题
|
较难
(0.4)
【推荐2】如图,已知等腰
,
,以
为直径作
交
于点
,过
作
的切线交
于点
,交
延长线于点
.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/2/2/570eea8f-0db1-4e1f-b905-6ee4cf92a3a1.png?resizew=239)
(1)求证:
.
(2)若
,
,求图中阴影部分的面积(结果用
表示).
![](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/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/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7dea2ae9d515f9ab351ad72306b776ee.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/2/2/570eea8f-0db1-4e1f-b905-6ee4cf92a3a1.png?resizew=239)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/761a77e11e1e45c2a8b2d34d22cf8e04.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df003447e98fd5ba9badd42177f345db.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/82773737609e65dea3c5c67099f1b10d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/86ebba6ed1add0fe647c0226614b9290.png)
您最近一年使用:0次
解答题-证明题
|
较难
(0.4)
【推荐1】如图甲,点C将线段AB分成两部分(AC>BC),如果
=
,那么称点C为线段AB的黄金分割点.某数学兴趣小组在进行课题研究时,由黄金分割点联想到“黄金分割线”,类似地给出“黄金分割线”的定义:直线l将一个面积为S的图形分成面积分别为S1,S2(S1>S2)的两部分,如果
=
,那么称直线l为该图形的黄金分割线.
![](https://img.xkw.com/dksih/QBM/2016/3/28/1574188368633856/1574188375236608/STEM/f38511c1c57a4cf88326ff4b2e6ec46a.png)
(1)如图乙,在△ABC中,∠A=36°,AB=AC,∠ACB的平分线交AB于点D,请问点D是否是AB边上的黄金分割点,并证明你的结论;
(2)若△ABC在(1)的条件下,如图丙,请问直线CD是不是△ABC的黄金分割线,并证明你的结论;
(3)如图丁,在Rt△ABC中,∠ACB=90°,D为斜边AB上的一点,(不与A,B重合)过D作DE⊥BC于点E,连接AE,CD相交于点F,连接BF并延长,与DE,AC分别交于点G,H.请问直线BH是直角三角形ABC的黄金分割线吗?并说明理由.
![](https://img.xkw.com/dksih/QBM/2016/3/28/1574188368633856/1574188375236608/STEM/43c9720a6bf34ed29a8cbc6a783d3ab7.png)
![](https://img.xkw.com/dksih/QBM/2016/3/28/1574188368633856/1574188375236608/STEM/774b5538f3f94a9a9e8e9523f9da9361.png)
![](https://img.xkw.com/dksih/QBM/2016/3/28/1574188368633856/1574188375236608/STEM/53d3c534dae347dbb190c09a8851afdd.png)
![](https://img.xkw.com/dksih/QBM/2016/3/28/1574188368633856/1574188375236608/STEM/aac0d61f110c427f8f03e503964ecf29.png)
![](https://img.xkw.com/dksih/QBM/2016/3/28/1574188368633856/1574188375236608/STEM/f38511c1c57a4cf88326ff4b2e6ec46a.png)
(1)如图乙,在△ABC中,∠A=36°,AB=AC,∠ACB的平分线交AB于点D,请问点D是否是AB边上的黄金分割点,并证明你的结论;
(2)若△ABC在(1)的条件下,如图丙,请问直线CD是不是△ABC的黄金分割线,并证明你的结论;
(3)如图丁,在Rt△ABC中,∠ACB=90°,D为斜边AB上的一点,(不与A,B重合)过D作DE⊥BC于点E,连接AE,CD相交于点F,连接BF并延长,与DE,AC分别交于点G,H.请问直线BH是直角三角形ABC的黄金分割线吗?并说明理由.
您最近一年使用:0次
解答题-证明题
|
较难
(0.4)
名校
【推荐2】已知:在
中,
,
,且点
,
分别在矩形
的边
,
上.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/30/ed6500f1-1de0-4682-aec4-d8faf5cac87d.png?resizew=502)
(1)如图
,当点
在
上时,求证:
;
(2)如图
,若
是
的中点,
与
相交于点
,连接
,求证:
;
(3)如图
,若
,
,
分别交
于点
,
,求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36e5e61804ce550636a0354e0a78a22d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0b9f4fe60b81ff21ca2acc95848a643d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/196ad60e8803f1c27fb8f1c584824ab3.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/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/30/ed6500f1-1de0-4682-aec4-d8faf5cac87d.png?resizew=502)
(1)如图
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdaa19de263700a15fcf213d64a8cd57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/637036d26c56bacaa700595eca3f37a8.png)
(2)如图
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c63e36329f5e0979f5ee776ac5d06327.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c4c865445dda4a59b6d5cb18fd74404.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42fda5d3bec762fcbc9f450be383b05c.png)
(3)如图
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ca7d1107389675d32b56ec097464c14.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e30e50e094cd2849e38859b36aad0b0c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/31e55e398e8520d8a36fb5a625a085b8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c63e36329f5e0979f5ee776ac5d06327.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/75a216a515262c356fc0fd017da627e3.png)
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解答题-问答题
|
较难
(0.4)
真题
名校
【推荐1】抛物线
与x轴分别交于点
,与y轴交于点
.
(2)如图1,
顶点P在抛物线上,如果
面积为某值时,符合条件的点P有且只有三个,求点P的坐标.
(3)如图2,点M在第二象限的抛物线上,点N在
延长线上,
,连接
并延长到点D,使
.
交x轴于点E,
与
均为锐角,
,求点M的坐标.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2299f88146e5a525b515a2ed36dfd1fa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f7d3d74fad4664bd2ac3071739d5c368.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fb3ea70a2c272af0b233796b6d13e0b2.png)
(2)如图1,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a6e93341a72402b2fb60869b63b1208a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a6e93341a72402b2fb60869b63b1208a.png)
(3)如图2,点M在第二象限的抛物线上,点N在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a4cfef623a9534b5708df5f95f1760a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1ad945f7fa3dd9a37d1f6114867f361d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7785afeeaf274892253d04b4f693b367.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d0679c805f1e663a890e405cca7b738d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be2e2c0d4ac2bd79f6cea7a9b1a50662.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6beda2518cf76da94d7ec9a813dcfa82.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/685516a27697104e83b311d76efa17aa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ca65c6e2f39e0b877852f63905a6738.png)
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解答题-证明题
|
较难
(0.4)
【推荐2】如图1,已知点O在四边形ABCD的边AB上,且
,OC平分
,与BD交于点G,AC分别与BD、OD交于点E、F.
![](https://img.xkw.com/dksih/QBM/2020/7/21/2510542119026688/2510588752633856/STEM/ccee07a328a84115ba8703f66c262189.png?resizew=470)
(1)求证:
;
(2)如图2,若
,求
的值;
(3)当四边形ABCD的周长取最大值时,求
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e860a3ae41f15eff26cc3cbf9fe2f270.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dc9f91270ddbe1cf3c1362e1b95aee14.png)
![](https://img.xkw.com/dksih/QBM/2020/7/21/2510542119026688/2510588752633856/STEM/ccee07a328a84115ba8703f66c262189.png?resizew=470)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/af99202ccd49163d6ffc433b333d1789.png)
(2)如图2,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7faabc484ce3666706c1beffda4bcfe2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5ca1cff7e12ceae15df29736638545a.png)
(3)当四边形ABCD的周长取最大值时,求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/810f9b4c1535bf75de1e31c164ccfe1e.png)
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