我们定义:等腰三角形中底边与腰的比叫做顶角正对(
),如图①,在
中,
,顶角A的正对记作
,这时
.容易知道一个角的大小与这个角的正对值也是相互唯一确定的.根据上述角的正对定义,解下列问题:
(1)
________.
(2)对于
,
的正对值
的取值范围是________.
(3)如图②,已知
,其中
为锐角,试求
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9800395d9cc0cb932d1257ae69a49ea8.png)
![](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/bf41b94bb22f385601fa21c3cf435470.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b717d72b448b6e3c355eed3d716441d7.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/10/13/73d2769e-4645-4c0e-8b43-734f79a7900e.png?resizew=270)
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8625e7f2aca24e57fbae7ce112513d63.png)
(2)对于
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be46c4b7a1b131d4b37fa43f1dcaa6ae.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3818a2c9919d358b4c3713396093822b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bf41b94bb22f385601fa21c3cf435470.png)
(3)如图②,已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15ee608882881caff2f1e223177424ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3818a2c9919d358b4c3713396093822b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bf41b94bb22f385601fa21c3cf435470.png)
20-21九年级下·福建龙岩·期中 查看更多[6]
福建省龙岩市紫金山实验中学2020-2021学年九年级下学期期中数学试题福建省宁德市古田县2020-2021学年九年级下学期期中数学试题广东省深圳市南山区荔香中学2022-2023学年八年级上学期期中模拟数学试题(已下线)专题24.6 解直角三角形章末拔尖卷-2023-2024学年九年级数学上册举一反三系列(华东师大版)(已下线)专题23.4 解直角三角形章末拔尖卷-2023-2024学年九年级数学上册举一反三系列(沪科版)福建省泉州市永春县第一中学2023-2024学年九年级上学期月考数学试题
更新时间:2023-09-22 22:14:24
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解答题-问答题
|
适中
(0.65)
【推荐1】如图,
中,
,动点
从点
出发,在
边上以每秒
的速度向点
匀速运动,同时动点
从点
出发,在
边上以每秒
的速度向点
匀速运动,运动时间为
秒
,连接
.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/3/19/54840ee4-d1ce-495e-b08b-4c3594e111f1.png?resizew=310)
(1)是否存在某一时刻
,使
的面积是
面积的
?若存在求出相应的
值,若不存在,
请说明理由.
(2)在运动过程中,是否存在某一时刻
,使
是等腰三角形?若存在,求出
的值;若不存在,请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd967903ed5a6f640a5b801ec8be0070.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e3b2d17dd85c13ed60489b4cb386375b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9abaeba15f3abdd877bc701af52c5cd9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/048b61a5fb5f420c6d7de88db5bc3aa5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c78d0ab561d0c9bb9099772c596af8bf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36a1b09c653185842513e24ebba60bb3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/577fb839669e9b32c0aa4b2a32335d34.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/892909e49156f7dcc0650fcd65243877.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/3/19/54840ee4-d1ce-495e-b08b-4c3594e111f1.png?resizew=310)
(1)是否存在某一时刻
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36a1b09c653185842513e24ebba60bb3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0c2b58424e893df4e01c912f87e09095.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0d41840af35e218a5639a2eff4d80b54.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36a1b09c653185842513e24ebba60bb3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9aa8a716a31b0f51b70fdf9bdb257909.png)
(2)在运动过程中,是否存在某一时刻
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36a1b09c653185842513e24ebba60bb3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0c2b58424e893df4e01c912f87e09095.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36a1b09c653185842513e24ebba60bb3.png)
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解答题-作图题
|
适中
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【推荐2】如图,P是等边三角形ABC中的一个点,PA=2,PB=2
,PC=4,试应用旋转作图探究得出三角形ABC的边长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7ffe8515ff6183c1c7775dc6f94bdb8.png)
![](https://img.xkw.com/dksih/QBM/2020/10/11/2568795194376192/2569655116980224/STEM/21b4cb3fc9f04f3d96504edb431fc589.png?resizew=138)
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解答题-证明题
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适中
(0.65)
名校
【推荐1】如图,矩形ABCD中,AD=3,AB=4,点P是对角线AC上一动点(不与A,C重合),连结BP,作PE⊥PB,交射线DC于点E,以线段PE,PB为邻边作矩形BPEF.过点P作GH⊥CD,分别交AB、CD于点G、H.
(1)求证:△PGB∽△EHP;
(2)求
的值;
(3)求矩形BPEF的面积的最小值.
(1)求证:△PGB∽△EHP;
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/46a56f51a6312441f9f07daf7e62ff41.png)
(3)求矩形BPEF的面积的最小值.
![](https://img.xkw.com/dksih/QBM/2020/11/14/2592506098229248/2596880460963840/STEM/4102e649c7a740309f2ee631abd19384.png?resizew=198)
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解答题-证明题
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名校
【推荐2】如图,AB是
的一条弦,点E是AB的中点,过点E作
于点C,过点B作
的切线交CE的延长线于点D.
(1)求证:
;
(2)若
,
,求
的半径.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/62c370e2b4dd09231557ec8dfb1c44ce.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e792b0ef3d542237ed0903194597651.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f0175d8a8ffcea569a8421c95c1dad2d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/490f0c21a0bfecc1447d54803af0b119.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
![](https://img.xkw.com/dksih/QBM/2021/6/7/2737956946378752/2799480530788352/STEM/fd0d5ebb-c92a-4b83-aa48-5575f655ebfe.png)
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解答题-问答题
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适中
(0.65)
【推荐1】如图所示,△ABC中,∠B=45°,∠C=30°,AB=
,求:AC的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf298f00799cbf34b4db26f5f63af92f.png)
![](https://img.xkw.com/dksih/QBM/2017/10/10/1792129648590848/1792950047006720/STEM/51bcee1297634c1495a2d1807cd8016b.png?resizew=181)
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解答题-问答题
|
适中
(0.65)
【推荐2】阅读下列材料:
题目:如图1,在
中,已知![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3818a2c9919d358b4c3713396093822b.png)
,
,
,请用
、
表示
.
解:如图2,作
边上的中线
,
于
,
则
,
,
,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/29a9325fba6d3f6bbc729dd0645403f3.png)
在
中,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6f6d7d7465385c9282a1a11acceb6e8a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/77604a9e3b3adaa1e252d9172fb4a3df.png)
根据以上阅读,请解决下列问题:
(1)如图3,在
中,
,
,
,求
,
的值
(2)上面阅读材料中,题目条件不变,请用
或
表示
.
![](https://img.xkw.com/dksih/QBM/2018/5/8/1940869164711936/1941672858451968/STEM/30610df7-9973-4f6a-bf58-4aec427e3ee3.png?resizew=560)
题目:如图1,在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0faed94a64b2dcfc6801b4fca0f16675.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3818a2c9919d358b4c3713396093822b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/40c325290a2e6182ea957e3131342f5b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7e3262fc038bbec5e7c8cc47df08bef7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ced06b71073e1bb777f326f06016ce17.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/79b01adc561735ff5be9bb97266918f2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5201fc26d013f6fb889933c0e32f5c53.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/328f4d3a80a80e08c3fd6544eadcb98f.png)
解:如图2,作
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b757f0c42ae5c9a2d6a4b19e5877b27.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
则
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f3497a268e125eab047f16182f5e2dae.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/78777bc8d82c3cd43c10f75fe42aa643.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a1730af061f824ebf648f85750bf27d1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/29a9325fba6d3f6bbc729dd0645403f3.png)
在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7e6c0088f87b066e8cc8a96c13a81806.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6f6d7d7465385c9282a1a11acceb6e8a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/77604a9e3b3adaa1e252d9172fb4a3df.png)
根据以上阅读,请解决下列问题:
(1)如图3,在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0faed94a64b2dcfc6801b4fca0f16675.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7e3262fc038bbec5e7c8cc47df08bef7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aa7aeb2a8d1437eeb4482c3b6ad9f315.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/efc6e4b936d7a800e839a30c3839574d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/79b01adc561735ff5be9bb97266918f2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/328f4d3a80a80e08c3fd6544eadcb98f.png)
(2)上面阅读材料中,题目条件不变,请用
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/79b01adc561735ff5be9bb97266918f2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5201fc26d013f6fb889933c0e32f5c53.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f590304526a01d93473193287ed4b00f.png)
![](https://img.xkw.com/dksih/QBM/2018/5/8/1940869164711936/1941672858451968/STEM/30610df7-9973-4f6a-bf58-4aec427e3ee3.png?resizew=560)
您最近一年使用:0次