如图,△ABC为等腰三角形,AC=BC,以边BC为直径的半圆与边AB,AC分别交于D,E两点,过点D作DF⊥AC,垂足为点F
(1)判断DF与⊙O的位置关系,并证明你的结论;
(2)若DF=3,EF=1,求弦EC的长.
(1)判断DF与⊙O的位置关系,并证明你的结论;
(2)若DF=3,EF=1,求弦EC的长.
![](https://img.xkw.com/dksih/QBM/2018/6/25/1974784617250816/1976308972142592/STEM/7339163076044a26902b0421b26dc792.png?resizew=165)
更新时间:2018-06-27 15:13:48
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【知识点】 证明某直线是圆的切线解读
相似题推荐
解答题-证明题
|
适中
(0.65)
【推荐1】如图,已知
与菱形ABCD的边BC相切于点E,与边AB相交于点F,连接EF.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/19/78f3eab5-4e83-4451-8f9a-6790919c702c.png?resizew=174)
(1)求证:CD是
的切线;
(2)若
的半径为2,
,求图中阴影部分的面积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3c20d0b44025a639ce3a92d639dae587.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/19/78f3eab5-4e83-4451-8f9a-6790919c702c.png?resizew=174)
(1)求证:CD是
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3c20d0b44025a639ce3a92d639dae587.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3c20d0b44025a639ce3a92d639dae587.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e4c60c85bdd52e0c75649d4df904b07.png)
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解答题-证明题
|
适中
(0.65)
【推荐2】如图,
为
的直径,点
在
上,
于点
且
平分![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1af6f30d09c412dcc347e29d19c0f7a9.png)
![](https://img.xkw.com/dksih/QBM/2020/4/23/2447719405740032/2447843160604672/STEM/2dad013a-3b55-4ad6-8b42-3fdd8a350309.png)
求证:
(1)直线
是
的切线;
(2)
.
![](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/cdb2dd10731b99c0f4f89ee957f8a239.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09e7170bb4a2ddcef39391a06c989162.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1af6f30d09c412dcc347e29d19c0f7a9.png)
![](https://img.xkw.com/dksih/QBM/2020/4/23/2447719405740032/2447843160604672/STEM/2dad013a-3b55-4ad6-8b42-3fdd8a350309.png)
求证:
(1)直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e52a8f07834cbbbe4224962672fbbb2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fbb1c5971af0a74a7fe7fa2c06ff26ac.png)
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