【计算与推理】
(1)如图1,
,
与
交于点
,
为
的中点,
,
,则
的长为_______;
和一块小三角板
,其中
,按如图2所示位置放置,使两个三角板的
角的顶点
重合.连接
、
,当
绕点
顺时针旋转时,试判断
,
的值是否变化?如果不变,请求出
,
的值,如果变化,请说明是如何变化并加以证明:
(3)现有一块足够大的木板,为参加学校科技节比赛,小明想在这块木板上裁出一个等边三角形(
)部件做模型,他的操作如下:
第一步:用两块大小不一的含
角的直角三角板
和
按如图3所示位置放置,其中
,含有
角的顶点
重合,分别延长
交于点
,连接
,得到
;
第二步:取
的中点
,分别连接
,
,得到
.
请问,按上述操作,裁得的
部件是否符合要求?请说明理由.
(1)如图1,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c0d3e0ae605bd0e18af759747676cafc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d004d2d115b477ade6af7ddb93db0df8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d004d2d115b477ade6af7ddb93db0df8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc34db5860990e51ba31edc8cdd077c2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/56512504254ab7f574a717dd6830fb33.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6541c0cb89f08aa4c937c0beb915e0a7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eca9b29cf78d7cbe030ca2c1fe5923cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e13b121a371524ec93dec325c5b0fe69.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d631f45bc652539853f236952afa5bbf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.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/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
(3)现有一块足够大的木板,为参加学校科技节比赛,小明想在这块木板上裁出一个等边三角形(
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ff39c7aa648afd1080206c8080ff79e.png)
第一步:用两块大小不一的含
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e13b121a371524ec93dec325c5b0fe69.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b9a32bd7a1b78b5a0ec562c4025aea8c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e2ac799536f7b41b9b60834933c9e8f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e13b121a371524ec93dec325c5b0fe69.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b194d0da4190a51a7aa4b6391f511cc3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df7f9f7952c4be18cb73393047c2ad75.png)
第二步:取
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/520976477250a5321f61d11947c3116f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ff39c7aa648afd1080206c8080ff79e.png)
请问,按上述操作,裁得的
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ff39c7aa648afd1080206c8080ff79e.png)
更新时间:2024-06-07 18:05:23
|
相似题推荐
解答题-问答题
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较难
(0.4)
【推荐1】如图1,在平面直角坐标系中,矩形
的顶点A、C分别在x轴负半轴、y轴正半轴上,
的长分别是方程
的两个根,且
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/28/652f241c-44ec-4928-a68f-a2be844d4b9b.png?resizew=286)
(1)求点B的坐标;
(2)如图2,过点A且垂直于
的直线交
轴于点F,在直线
上截取
,过点D作
轴于点E,求经过点D的反比例函数的关系式;
(3)在(2)的条件下,在y轴上是否存在一点P,使以D,E,P为顶点的三角形与
相似?若存在,求出点P的坐标;若不存在,请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3241d7fedd89d85711acd7a2635298af.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2bd3724385f98a2415ba27f8df4c31d0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/58b60076ad90f01480cc1b28fc84b1db.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f2da1d50433aecf541991fd0f01773cb.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/28/652f241c-44ec-4928-a68f-a2be844d4b9b.png?resizew=286)
(1)求点B的坐标;
(2)如图2,过点A且垂直于
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d053b14c8588eee2acbbe44fc37a6886.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9fc13fe21e64d9b45614ed43be847904.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7e8344999680784650f29a28159b1edf.png)
(3)在(2)的条件下,在y轴上是否存在一点P,使以D,E,P为顶点的三角形与
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/173bc7a36757d77f01213411edd25241.png)
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名校
【推荐2】在
中,点
为线段
上一动点,点
为射线
上一动点,连接
,
.
,当点
在线段
上时,
交于点
,点
为
中点.
①如图1,若
,求
的长度;
②如图2,点
为线段
上一点,连接
并延长交
的延长线于点
.若点
为
中点,
,求证:
.
(2)如图3,若
.当点
在线段
的延长线上时,连接
,将
沿
所在直线翻折至
所在平面内得到
,连接
,当
取得最小值时,
内存在点
,使得
,当
取得最小值时,请直接写出
的值.
![](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/0dc5c9827dfd0be5a9c85962d6ccbfb1.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/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1d8c8d9e5ebcf7a6f6a5595e9be75c7a.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/ba83afe4ade6624b283331a18bdf2ca1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
①如图1,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cc9a9bc9aeef0af1125f49e1f93530ca.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
②如图2,点
![](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/91f3956f008cc29ca4bae44a087d5427.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73465a1f9aa03481295bf6bd3c6903ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e42887d9bf31c1dd99f13c39e63c9ab9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/50d412b6548de7c823da6ce80af85418.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/efedaf020e72e4d08fe422421de67df6.png)
(2)如图3,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c4ce40c4594ac8c1e09e47c5f7e6539c.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/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3a0acc93490a6a784eb62201d93dd93d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e52a8f07834cbbbe4224962672fbbb2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/366f51d41a3989f78882fb1358fa6119.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d50703c46b6153945d718b198f03b4b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d50703c46b6153945d718b198f03b4b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf3834d7ec7531f3c3c0ce9b286f7a49.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f875d939c8040a5cf196f928955af546.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ce16a8493d8934ef0df0bbd27c929af.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4ffe67d727255ec27cc49abcffea3f2c.png)
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【推荐1】已知
中,
;
中,
;
,点A.D.E在同一直线上,AE与BC相交于点F,连接BE.
![](https://img.xkw.com/dksih/QBM/2021/1/6/2630329588940800/2634557355802624/STEM/b3ed9470-c689-45df-ac77-98c3b60fe2b0.png?resizew=599)
(1)如图1,当
时,
①请直接写出
和
的形状;
②求证:
;
③请求出
的度数.
(2)如图2,当
时,请直接写出:
①
的度数;
②若
,
,线段AF的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b10134e7a46e6f6f7cb9d5e2371727d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2689f0ce5ab3467d8214794d8acb2bd6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2ead706ccc238d868654030a3626847c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5c810195143c802ec54797bc68d3880c.png)
![](https://img.xkw.com/dksih/QBM/2021/1/6/2630329588940800/2634557355802624/STEM/b3ed9470-c689-45df-ac77-98c3b60fe2b0.png?resizew=599)
(1)如图1,当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/97cf714ffb3fd5917a76b191640b55fe.png)
①请直接写出
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2689f0ce5ab3467d8214794d8acb2bd6.png)
②求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c503e29373e8d87134bdb46bd3912910.png)
③请求出
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1a55a1a244f81097e05e715b69580faa.png)
(2)如图2,当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/33ac762a2899a58faa0d3ab44f1281fa.png)
①
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1a55a1a244f81097e05e715b69580faa.png)
②若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8934fd75e713409bc4b3dbfb40a17d6a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60634341a9603e24b2bbc6960abe3d31.png)
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解题方法
【推荐2】将两块全等的三角板如图①摆放,其中
,
.
![](https://img.xkw.com/dksih/QBM/2021/5/13/2720380719030272/2731317539078144/STEM/698723ab-86f9-4e47-acc7-3dea46d4c502.png)
(1)将图①中的
顺时针旋转后得到图②,点
是
与
的交点,点
是
与
的交点.若
,请判断
的形状,并说明理由;
(2)将图①中的
顺时针旋转45°得图③,点
是
与
的交点,点
是
与
的交点,求证:
;
(3)在(2)的条件下,如图④,在
上取一点
,连接
、
,设
,当
时,求
的面积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab1548b19858f612eb54de22d3417b80.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fb6a09c3c0c0fd2aaded7a778576e7e0.png)
![](https://img.xkw.com/dksih/QBM/2021/5/13/2720380719030272/2731317539078144/STEM/698723ab-86f9-4e47-acc7-3dea46d4c502.png)
(1)将图①中的
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f2f73e4d0557ca664d1edd70b7275667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ee8456443402a25b1e25d35ff7e1c98.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11ddc92d84d188c66b435664a7e7b5a4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2cc2854df1e5314734576891b8372a9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08fa5b7ee3c02add5668fcdfd13e4b6f.png)
(2)将图①中的
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f2f73e4d0557ca664d1edd70b7275667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ee8456443402a25b1e25d35ff7e1c98.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11ddc92d84d188c66b435664a7e7b5a4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/378ab247cf28dd1b17d48a508fa92176.png)
(3)在(2)的条件下,如图④,在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d7f6f93171329d508d491143b9d71f7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e69d2b798744645af88a4fa411344a83.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/892909e49156f7dcc0650fcd65243877.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8e1f4f255d191786f7d330d278868c2d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca9502482ff9df5b1ca52304cd4783bd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68ae0df0b9934dd820e797e501e7074b.png)
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【推荐1】如图,抛物线y=–
x2+bx+c过点A(3,0),B(0,2).M(m,0)为线段OA上一个动点(点M与点A不重合),过点M作垂直于x轴的直线与直线AB和抛物线分别交于点P、N.
(1)求直线AB的解析式和抛物线的解析式;
(2)如果点P是MN的中点,那么求此时点N的坐标;
(3)如果以B,P,N为顶点的三角形与△APM相似,求点M的坐标.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d599cb4a589f90b0205f24c2e1fa021e.png)
(1)求直线AB的解析式和抛物线的解析式;
(2)如果点P是MN的中点,那么求此时点N的坐标;
(3)如果以B,P,N为顶点的三角形与△APM相似,求点M的坐标.
![](https://img.xkw.com/dksih/QBM/2019/3/8/2156160666558464/2157399523188736/STEM/706e08da76894fdaa1f7920bd6d068a7.png?resizew=276)
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【推荐2】习过相似三角形后,刘老师布置了一道思考题.
问题情境:如图1,等腰三角形ABC中,
,CD为AB边上的中线,M为CD上一个动点,
于点E,连接CE,若点N为AC上一个动点,连接EN,当
,
时,求EN的最小值.
小明在分析这道题时,发现思路不明显,他采用从特殊到一般的方法进行探究,以下是他的探究过程,请仔细阅读,并完成下列任务.
![](https://img.xkw.com/dksih/QBM/2022/4/26/2973075254190080/2979826205917184/STEM/fdebc84b-59c8-44d3-91ac-d492355665b2.png?resizew=394)
任务:
(1)小明在分析一中判断EN的最小值时运用了______原理;(填序号)
①两点之间线段最短;②垂线段最短;③平行线间的距离;④点到圆的距离.
(2)请完成分析二的证明;
(3)请直接写出问题情境中EN的最小值.
问题情境:如图1,等腰三角形ABC中,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b10134e7a46e6f6f7cb9d5e2371727d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6fceab837209b0fd306dd7ff1381e6e7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c3ad4c0ba3a6750537789844d0ec419d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/305a88d4e0249bd16d48eda01331d2d4.png)
小明在分析这道题时,发现思路不明显,他采用从特殊到一般的方法进行探究,以下是他的探究过程,请仔细阅读,并完成下列任务.
![](https://img.xkw.com/dksih/QBM/2022/4/26/2973075254190080/2979826205917184/STEM/fdebc84b-59c8-44d3-91ac-d492355665b2.png?resizew=394)
原题中动点较多,小明准备先从动点的条件入手分析: 分析一:如图2,等腰三角形ABC中, ![]() 若 ![]() ![]() 点N为AC上一个动点,连接EN,探究EN是否存在最小值; 过程:连接AE,∵CD垂直平分AB, ![]() ∴ ![]() ![]() ![]() ∵ ![]() ![]() ![]() ∵ ![]() ![]() ![]() ∴ ![]() ![]() ∴ ![]() ![]() ∴ ![]() ![]() 分析二:如图3,等腰三角形ABC中, ![]() 若 ![]() ![]() 连接CE,EN,求证: ![]() |
(1)小明在分析一中判断EN的最小值时运用了______原理;(填序号)
①两点之间线段最短;②垂线段最短;③平行线间的距离;④点到圆的距离.
(2)请完成分析二的证明;
(3)请直接写出问题情境中EN的最小值.
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【推荐3】如图,在平面直角坐标系中,四边形OABC 的边OC 、OA 分别与 x 轴、 y 轴重合, AOC 90,BCO 45, AB // OC , BC 6
,点C 的坐标为 9,0.
![](https://img.xkw.com/dksih/QBM/2019/7/27/2256040996069376/2283520794099712/STEM/59946412cd68476b9fa5de08556d87bb.png?resizew=175)
![](https://img.xkw.com/dksih/QBM/2019/7/27/2256040996069376/2283520794099712/STEM/80eb41d135c24adbb11c06fc56fbe6ed.png?resizew=137)
(1)求点 B 的坐标;
(2)若直线 DE 交四边形的对角线 BO 于点 D ,交 y 轴于点 E ,且OE 2 , OD 2BD ,求:
① ODE 的面积;
②点 D 的坐标.
(3)在(2)的条件下,坐标平面内是否存在点 P ,使以O 、E 、P 、D 为顶点的四边形是平行四边形? 若存在,请直接写出点 P 的坐标;若不存在,请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf298f00799cbf34b4db26f5f63af92f.png)
![](https://img.xkw.com/dksih/QBM/2019/7/27/2256040996069376/2283520794099712/STEM/59946412cd68476b9fa5de08556d87bb.png?resizew=175)
![](https://img.xkw.com/dksih/QBM/2019/7/27/2256040996069376/2283520794099712/STEM/80eb41d135c24adbb11c06fc56fbe6ed.png?resizew=137)
(1)求点 B 的坐标;
(2)若直线 DE 交四边形的对角线 BO 于点 D ,交 y 轴于点 E ,且OE 2 , OD 2BD ,求:
① ODE 的面积;
②点 D 的坐标.
(3)在(2)的条件下,坐标平面内是否存在点 P ,使以O 、E 、P 、D 为顶点的四边形是平行四边形? 若存在,请直接写出点 P 的坐标;若不存在,请说明理由.
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解题方法
【推荐1】如图,在Rt△ABC中,
,
角平分线交BC于O,以OB为半径作⊙O.
(1)判定直线AC是否是⊙O的切线,并说明理由;
(2)连接AO交⊙O于点E,其延长线交⊙O于点D,
,求
的值;
的半径为3,求AC的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd529787307f682da7b6e981e789104f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7cbce11aa19b8bd2bf6ee5a834e005de.png)
(1)判定直线AC是否是⊙O的切线,并说明理由;
(2)连接AO交⊙O于点E,其延长线交⊙O于点D,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2630d7520695b4fe48f66b87165edbe3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a5f276ad76c075f4be32ad326d223cf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
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【推荐2】设等边三角形的内切圆半径为
外接圆半径为
,平面内任意一点
到等边三角形中心的距离为
若满足
则称点
叫做等边三角形的中心关联点.在平面直角坐标系
中,等边
的三个顶点的坐标分别为
.
(1)①等边
中心的坐标为 ;
②已知点
在
中,是等边
的中心关联点的是 ;
(2)如图1,过点
作直线交
轴正半轴于
使
.
![](https://img.xkw.com/dksih/QBM/2020/4/22/2447129748832256/2448262676070400/STEM/86951af3310d43b69d059559c1120452.png?resizew=372)
①若线段
上存在等边
的中心关联点
求
的取值范围;
②将直线
向下平移得到直线
当
满足什么条件时,直线
上总存在等边
的中心关联点;
(3)如图2,点
为直线
上一动点,
的半径为
当
从点
出发,以每秒
个单位的速度向右移动,运动时间为
秒.是否存在某一时刻
使得
上所有点都是等边
的中心关联点?如果存在,请直接写出所有符合题意的
的值;如果不存在,请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f662245ef3eda9a64a66c51ccec119b4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4aa0df7f1e45f9de29e802c7f19a4f64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7cb9fef4d5f2e8f3d99976ca14b04bc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e6ba879d8d0e7262b38ced2fa5befdf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7ee31829d0d4d5f779a957d7df8058ab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/966adfcbfc60699760b3ff0314a76580.png)
(1)①等边
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
②已知点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b0ac9ac845d601e0e51813e23eb1d085.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/927456b0989846a2f1573844bbaa2105.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
(2)如图1,过点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/98914a2f34d457acf18e36d3b6eac5f6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/26091275e83ad678e2933abe0cd336ee.png)
![](https://img.xkw.com/dksih/QBM/2020/4/22/2447129748832256/2448262676070400/STEM/86951af3310d43b69d059559c1120452.png?resizew=372)
①若线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d50703c46b6153945d718b198f03b4b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b0f72b4b6f96efcb6ac360385e4efe40.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
②将直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d50703c46b6153945d718b198f03b4b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7cd7b3ef97841c47875a7cdbc2407dd2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c94bb12cee76221e13f9ef955b0aab1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c15fb18163df0690365a0d2e7ee88f5a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
(3)如图2,点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eefa44964db83759aff6fc8dd7ef8f28.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb52bba9798c625c7cd778636bceea32.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a18b9055334fbdfc0bb53e2531a34397.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/13c63f9522aa44add2a2d3c2acd6a795.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdaa19de263700a15fcf213d64a8cd57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36a1b09c653185842513e24ebba60bb3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e87a321d246e9bf366730a54d261d70d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb52bba9798c625c7cd778636bceea32.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36a1b09c653185842513e24ebba60bb3.png)
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解题方法
【推荐3】AC,BD是四边形ABCD的对角线,AB=AC,∠ABC+∠ADC=90°.
(1)如图1.若∠ABC=60°,求证:BD2=AD2+CD2;请参照大胖同学的思路完成如下证明过程.
证明:以AD为边作等边
ADE,连接BE,因为∠ABC=60°,AB=AC,所以
ABC是等边三角形,
![](https://img.xkw.com/dksih/QBM/2021/10/13/2828498226315264/2834901084872704/STEM/07a77bd8-b32b-44c8-b79f-b190cb25e54f.png)
(2)如图2,若∠ABC=45°,写出一个等式,表示BD,AD,CD之间的数量关系,并给出证明;
(3)如图3,若∠ABC=30°,AD
BC,直接写出
的值.
(1)如图1.若∠ABC=60°,求证:BD2=AD2+CD2;请参照大胖同学的思路完成如下证明过程.
证明:以AD为边作等边
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce4cba95fc7d4853a243f8e3fb20ce70.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce4cba95fc7d4853a243f8e3fb20ce70.png)
![](https://img.xkw.com/dksih/QBM/2021/10/13/2828498226315264/2834901084872704/STEM/07a77bd8-b32b-44c8-b79f-b190cb25e54f.png)
(2)如图2,若∠ABC=45°,写出一个等式,表示BD,AD,CD之间的数量关系,并给出证明;
(3)如图3,若∠ABC=30°,AD
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895d6f710d5f67e1d4c7408d50d77281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/902608e81b1b1e7b04cff53215a633a1.png)
![](https://img.xkw.com/dksih/QBM/2021/10/13/2828498226315264/2834901084872704/STEM/44a52a4e-faa3-46a2-bac4-af7c558f133c.png)
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