如图①,AB是⊙O的直径,AC是弦,直线EF和⊙O相切于点C,AD⊥EF,垂足为D.
(1)求证:∠DAC=∠BAC;
(2)若把直线EF向上平行移动,如图②,EF交⊙O于G、C两点,若题中的其它条件不变,猜想:此时与∠DAC相等的角是哪一个?并证明你的结论.
![](https://img.xkw.com/dksih/QBM/2011/12/6/1573297077919744/1573297115021312/STEM/2b45b129-2419-49bc-92d1-04b8202c84c9.png?resizew=162)
(1)求证:∠DAC=∠BAC;
(2)若把直线EF向上平行移动,如图②,EF交⊙O于G、C两点,若题中的其它条件不变,猜想:此时与∠DAC相等的角是哪一个?并证明你的结论.
![](https://img.xkw.com/dksih/QBM/2011/12/6/1573297077919744/1573297115021312/STEM/2b45b129-2419-49bc-92d1-04b8202c84c9.png?resizew=162)
![](https://img.xkw.com/dksih/QBM/2011/12/6/1573297077919744/1573297115021312/STEM/6a92e2c3-af0d-4fb4-bed5-01f038148e01.png?resizew=158)
11-12九年级上·河北秦皇岛·期中 查看更多[5]
(已下线)2011-2012年河北省北戴河区第二中学九年级上学期期中考试数学卷(已下线)2011年北戴河区第二中学九年级上学期期中考试数学卷(已下线)2011-2012学年河北省北戴河区第二中学初三上学期期中考试数学试卷华东师大版九年级数学下册期末综合检测试卷山西省吕梁市兴县2020-2021学年九年级上学期期末数学试题
更新时间:2016-12-05 05:44:05
|
相似题推荐
解答题-证明题
|
适中
(0.65)
【推荐1】如图,在△ABC中,AB=AC,以AB为直径的⊙O分别交AC,BC于点D,E,点F在AC的延长线上,且∠CBF=
∠CAB. 求证:直线BF是⊙O的切线.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f89eef3148f2d4d09379767b4af69132.png)
![](https://img.xkw.com/dksih/QBM/2019/2/22/2146236508823552/2147129822085120/STEM/65f3c70ea89d4c728880c7ed4f8bf94b.png?resizew=154)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
【推荐2】如图,已知
内接于
,
是
的直径,连接
平分
.
(1)求证:
;
(2)若
,则
的长为 .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/84fc5a625fe80f7358ec0a67405a2667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/246a86f34603eaf2e6a948681b831b0d.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/3/4/e3a1b1ff-c655-47fb-a390-32f0b1a0228b.png?resizew=134)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/edc3fb27803d7ee3d3a97781858f7d37.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/267ace52b64e1e7dfc5211e033255b7d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
【推荐1】如图,已知点
是以
为直径的半圆上一点,
是
延长线上一点,过点
作
的垂线交
的延长线于点
,连结
,且
.
是
的切线;
(2)若
,
,求
的半径.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.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/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f21678a0009eb39b6886653d295b09a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a1e5abd728134f3926e6c7828d0f3e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dfb08f6a798dc293f3d8de281190f65e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
【推荐2】如图,
中,
,点
为
边上一点,以
为半径的
与
相切于点
,分别交
边于点
.
(1)求证:
平分
;
(2)若
,求
的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd967903ed5a6f640a5b801ec8be0070.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7e3262fc038bbec5e7c8cc47df08bef7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef4113c492885ba7c47fe42ac792578f.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/7dec2ca6438c82b43f746057d8129885.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad056c25c0fdcbcc765eb5cbc6093f2b.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/6/5/24c6be96-f289-445f-aae9-0251de239e68.png?resizew=168)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7cbce11aa19b8bd2bf6ee5a834e005de.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a66fb4160a94c49c1c4a6f8c867abb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
您最近一年使用:0次