如图(1),在△OAB中,AB=2cm,OB=4cm,点A在半径为2
cm的⊙O上.
![](https://img.xkw.com/dksih/QBM/2022/4/5/2951812424728576/2965871353462784/STEM/93a8e509-a956-4635-a554-a7a64a8d60c9.png?resizew=587)
(1)求证:直线AB与⊙O相切;
(2)如图(2),CD切⊙O于点C,CD=2cm,连结BD,交⊙O于点E,F.
①求证:DE=BF;
②若EF两点重合,如图3,求阴影部分的面积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7ffe8515ff6183c1c7775dc6f94bdb8.png)
![](https://img.xkw.com/dksih/QBM/2022/4/5/2951812424728576/2965871353462784/STEM/93a8e509-a956-4635-a554-a7a64a8d60c9.png?resizew=587)
(1)求证:直线AB与⊙O相切;
(2)如图(2),CD切⊙O于点C,CD=2cm,连结BD,交⊙O于点E,F.
①求证:DE=BF;
②若EF两点重合,如图3,求阴影部分的面积.
更新时间:2022-04-25 17:43:37
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相似题推荐
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【推荐1】某兴趣小组开展综合实践探究活动:
已知
为等边三角形,点
,
分别在边
,
上,且
,
,
相交于点
,连接
.探究过程如下:
(1)①如图1,当点
为
中点时,
;
②如图2,当
时,
;
(小智积极思考,提供如下解题思路:
延长
至点
,使得
,连接
,
.
,
,
,
.
.
又
,
.
又
,
是等边三角形.……)
【类比探究】
(2)如图3,当
时,求
的值;
【拓展延伸】
(3)①当
时,直接写出
的值(用含
的式子表示);
②当点
在
延长线上,点
在
延长线上时,且
,直线
,
相交于点
,连接
,请直接写出
的值(用含
的式子表示).
已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.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/d42218a68301d770accaaefb96b19f8a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63a253c7fdf589ee3dece13d5b5b5732.png)
(1)①如图1,当点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a1de94901207fc22febd4bf4760fd970.png)
②如图2,当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cc9b0d3cf342e065b4c8e21443bfbfbc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8228b61810f3d48ab3bb118d0e6a07c6.png)
(小智积极思考,提供如下解题思路:
延长
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc5adb5eb60ae4435a12d93854066298.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/587eab9a26310dc294effac917a4178a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/274cf35acb4a1748d15c39d15a9bea7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4cae70b8a9d2d2e96dea62c00ced04b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c4fb9bc6163bd3f8aa1a8b0a70c9cbf8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6fbf18a89d2bc8795a4393d02b0f970e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d42218a68301d770accaaefb96b19f8a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/93fe27a2f7a406c1dbbe4d95db109744.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/33414fdfa12f64e52fd438690063b1f0.png)
又
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed62aa0840db9c22386593d596593de4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6711c81a608af5754aa603b820753002.png)
又
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/93cc50ad2ba6b7f2571f6d83a689c969.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9dd2f4363d0d5996571b458d2539bde2.png)
【类比探究】
(2)如图3,当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/942a9a6bde4a5b9803b68b1e9065de62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/424dd73a238dad799c9296e9ff829253.png)
【拓展延伸】
(3)①当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b3ca85a8426af15089c9a0e599b0748a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/424dd73a238dad799c9296e9ff829253.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
②当点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9abaeba15f3abdd877bc701af52c5cd9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7aed9117f66f0f21602ccd31cce376ff.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63a253c7fdf589ee3dece13d5b5b5732.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dcce0893aa84f73e5f5d05ddab5d0848.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
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【推荐2】如图,已知正方形ABCD中,点E是直线BD上一动点,以AE为边作正方形AEFG,连接BG.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/7/1/4888e871-350e-446c-b8eb-4f9b1261339c.png?resizew=420)
(1)如图1,当点E在线段BD上时,ED与BG的数量关系为______,位置关系为______;
(2)如图2,当点E在DB的延长线上时,(1)中的结论是否依然成立,并说明理由;
(3)如图3,在图2中,延长DA交BG于点M,连接FM,已知
,
.
①求FM的长;
②已知正方形AEFG的对角线的交点为O,连接BO,求出BO的长.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/7/1/4888e871-350e-446c-b8eb-4f9b1261339c.png?resizew=420)
(1)如图1,当点E在线段BD上时,ED与BG的数量关系为______,位置关系为______;
(2)如图2,当点E在DB的延长线上时,(1)中的结论是否依然成立,并说明理由;
(3)如图3,在图2中,延长DA交BG于点M,连接FM,已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c406e7d1e7977dd5b30ef81cfdc8e8d2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60634341a9603e24b2bbc6960abe3d31.png)
①求FM的长;
②已知正方形AEFG的对角线的交点为O,连接BO,求出BO的长.
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【推荐3】在平面直角坐标系中,点
在y轴正半轴上,直线l平分坐标系的第二、四象限,点B是直线l上一动点.
最短时,点B的坐标为________;(结果均用a表示)
(2)如图2,当
轴,且垂足为点A时,以
为边作正方形
,M在x轴的正半轴,且
,以
为边在x轴上方作正方形
,连接
,若
,两个正方形面积之和为20,求
的面积;
(3)如图3,当
轴,且垂足为点A时,点F在线段
上运动(不与端点重合),点C是线段
的中点,连接
,以A为直角顶点,
为直角边在第二象限内作等腰
,连接
,交
于点G,探究线段
与
的关系,并说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d8da179d60dd9ec6ece6de442ae1b06.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
(2)如图2,当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2ea84cba8ccd585ad1da1fd204bc3e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef4113c492885ba7c47fe42ac792578f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bf4c18d2e9b719fb0b7bdf5162c1ef6a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a40a1e961ba3603c64107fb556db6c10.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aaf3369e0ea90e8d5cf4b6b3c45c0fd8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/62ea1231c33f1357206dff422d7cf0d1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f50b3ae183997b707d16eb4e7f6712fa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aa69c6f2206f7ab12cb1358d5b19c6e2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c8bd01cd837bc582032269ea383200b1.png)
(3)如图3,当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2ea84cba8ccd585ad1da1fd204bc3e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b90e0f35eda1a729fed485f83da5ea9d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/274cf35acb4a1748d15c39d15a9bea7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ec2a74cd3134a825d7924a01c8e633ea.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/636a1313a0ba873f9d5e4f67beec21d4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a299d2b999568e80be8005565ba209a4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a299d2b999568e80be8005565ba209a4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
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【推荐1】如图1,四边形
、
为全等的矩形.且矩形
的对角线交于点E,点A在
上,
.将矩形
绕点E顺时针旋转а角
,如图2,
、
与
分别相交于N、M.
![](https://img.xkw.com/dksih/QBM/2015/4/29/1573833411837952/1573833418244096/STEM/367fb0e0e71f49b08ba055f4af3eee6d.png?resizew=347)
(1)求证:
;
(2)若
,求旋转角а的大小.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/611f100dcfa7803db6eb233e2e7f2dab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/31e55e398e8520d8a36fb5a625a085b8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/392b9e1a179a6676362679354a9e7e51.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/611f100dcfa7803db6eb233e2e7f2dab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad0fef6d9c3728c72031987b7782c20c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/91f3956f008cc29ca4bae44a087d5427.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f7c57b07f75e97d9f84718bd495ebcf4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://img.xkw.com/dksih/QBM/2015/4/29/1573833411837952/1573833418244096/STEM/367fb0e0e71f49b08ba055f4af3eee6d.png?resizew=347)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a194fd6313939a1bd9194ba5705bfe12.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d0d04fa881aa0bdedf27af48f18c88b1.png)
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【推荐2】平移、旋转、翻折是几何图形的最基本的三种图形变换,利用图形变换可将分散的条件相对集中,以达到解决问题的目的.
内一点,
.求
的度数.
解:将
绕点A旋转到
的位置,连接
,则
是 三角形.
∵
,
∴![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8eeaec44d0a4a0302f02c000d135205d.png)
∴
为 三角形.
∴
的度数为 .
(2)类比延伸:如图2,在正方形
内部有一点P.连接
,若
,求
的长;
(3)拓展迁移:如图3,若点P是正方形
外一点
,求
的度数.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1ca9899fbb736aa2963ab88cf2919ace.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb686e4f5e3938575bc547e849d5513f.png)
解:将
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9524e3810e06dc781285f1289e75d653.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/77565c0aab1ab567e92dc1aee447e271.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a99e1ad0d6fb0f13be56d09086366c5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd2f90f1f950f19b10ee0b1852cec730.png)
∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ce13df595fb01b3c7a613da1d34d8f7.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8eeaec44d0a4a0302f02c000d135205d.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ea8760d054667817c5b0c7889d111b59.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb686e4f5e3938575bc547e849d5513f.png)
(2)类比延伸:如图2,在正方形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/92c7267e5313b9b00ef22c94a479fc34.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5e78424ce65f704c5e6aedc299a5349b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
(3)拓展迁移:如图3,若点P是正方形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e04b36334d4d055005da1dcb164cb117.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb686e4f5e3938575bc547e849d5513f.png)
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【推荐1】已知
内接于以
为直径的
,过点
作
的切线交
的延长线于点
,且
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/6/b2b48853-d221-4f78-a84a-63c427f0004f.png?resizew=138)
(1)求证:
;
(2)求
的度数;
(3)在切线
上截取
,连接
,判断直线
与
的位置关系,并证明.
![](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/3d97cdc586744d208b6f69c9813af977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7dea2ae9d515f9ab351ad72306b776ee.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9fbacc433ff870f19048de57ad18f332.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/6/b2b48853-d221-4f78-a84a-63c427f0004f.png?resizew=138)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b021d115c90e0ed548a0d756d55c35f5.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c9d16fab0f52c8af5abba0bf19a06ea0.png)
(3)在切线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e52a8f07834cbbbe4224962672fbbb2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3b1d267eeb09c171c3e847f0597be31c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccaee8f228ff24e7c89879bb5b999cf2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccaee8f228ff24e7c89879bb5b999cf2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
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【推荐2】如图,AB为⊙O的直径,点C,D是⊙O上的点,AD平分∠BAC,过点D作AC的垂线,垂足为点E.
(1)求证:DE是⊙O的切线;
(2)延长AB交ED的延长线于点F,若⊙O半径的长为3,tan∠AFE=
,求CE的长.
(1)求证:DE是⊙O的切线;
(2)延长AB交ED的延长线于点F,若⊙O半径的长为3,tan∠AFE=
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b2a698891d42c70b597f0da4f215f09.png)
![](https://img.xkw.com/dksih/QBM/2021/1/20/2640121220718592/2640804855316480/STEM/a62227fd55ff440f8d2030b0e8de19fd.png?resizew=133)
您最近一年使用:0次
解答题-问答题
|
较难
(0.4)
【推荐1】如图,在
中,
,把
绕点A顺时针旋转,使
落到
延长线上的
处,得到
,点B的对应点为D,点C的对应点为E,旋转过程中得到两条弧
,
,
与
交于点F,连接
.
(1)求
的度数;
(2)若
,求阴影部分的面积;
(3)若
,弧BD与线段
只有一个公共点D,直接写出线段
的取值范围.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7c646c683fbe522edb7ea54fd3ad873d.png)
![](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/9abaeba15f3abdd877bc701af52c5cd9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a25c28359f8d8da9eaf4672a6cf8ae4f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8192018a58bb1fe23769a48a4d9042ed.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0bd6ffb78dad3375efa3b08ab518553d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/95bf05f26cb828910e47ddb5c8dedd66.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/6/20/96b53da9-d6ec-4597-a4ec-1ef400004189.png?resizew=162)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/384da7acfefa7c656eaca2df173f0cb6.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/454328a8e75953fdb0835ce80d9566e3.png)
(3)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1682d306c38087d9e6f7efb9cec596a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.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,⊙O的直径AB=2
,点C为⊙O上一点,CF为⊙O的切线,OE⊥AB于点O,分别交AC,CF于D,E两点.
![](https://img.xkw.com/dksih/QBM/2022/4/7/2952829603061760/2953164934176768/STEM/e1c0401488cc48d0885e8a187cb842c7.png?resizew=146)
(1)求证:ED=EC;
(2)若∠A=30°,求图中两处(点C左侧与点C右侧)阴影部分的面积之和.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7ffe8515ff6183c1c7775dc6f94bdb8.png)
![](https://img.xkw.com/dksih/QBM/2022/4/7/2952829603061760/2953164934176768/STEM/e1c0401488cc48d0885e8a187cb842c7.png?resizew=146)
(1)求证:ED=EC;
(2)若∠A=30°,求图中两处(点C左侧与点C右侧)阴影部分的面积之和.
您最近一年使用:0次