我们知道,三角形的中位线平行于三角形的第三边,并且等于第三边的一半,如何证明三角形中位线定理呢?
(1)【方法回顾】证明:三角形中位线定理.
已知:如图,在
中,
、
分别是
、
的中点.
求证:
,
.
证明三角形中位线性质定理的方法很多,但多数都需要通过添加辅助线构图去完成,下面是其中一种证法的添加辅助线方法,阅读并完成填空:
添加辅助线,如图1,在
中,过点
作
,与
的延长线交于点
.可证
______,根据全等三角形对应边相等可得
,然后判断出四边形
是______,根据图形性质可证得
,
.
(2)【方法迁移】如图2,在四边形
中,
,
,
,
为
的中点,
、
分别为
、
边上的点,若
,
,
,求
的长.
(3)【定理应用】如图3,在
中,
,
是
的中点,
是边
上一点,
,延长
至点
,使
,延长
交
于点
,直接写出
的值(用含
的式子表示).
(1)【方法回顾】证明:三角形中位线定理.
已知:如图,在
![](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/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c436f108fd4921dae15ecff19270237e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/950e82a0f9712457f2dd9f8a93f8a217.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/6/7/83dd4fe3-36f7-4435-9765-7319b99cff7d.png?resizew=150)
证明三角形中位线性质定理的方法很多,但多数都需要通过添加辅助线构图去完成,下面是其中一种证法的添加辅助线方法,阅读并完成填空:
添加辅助线,如图1,在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fe9f641563e8533a5bb39188aa7cc182.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aa2f359d983ea52797dfc76023366a8d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6fe6d389a6c448d92b79d89bc9e8489f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/211c130e20ea36d96e88927f88df956e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c436f108fd4921dae15ecff19270237e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/950e82a0f9712457f2dd9f8a93f8a217.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/6/7/bdbe31a0-2ab3-4ab0-9199-3a509282c045.png?resizew=192)
(2)【方法迁移】如图2,在四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4adf90a8c2b29334cdc5aa5b554991f9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8f89deb952f57f4b3fa4887b098b7b91.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0b0ce914a50f5376766d5065e5f13d96.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bae2736ade41af30db54753220a71eaf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/169145cfb31e4fc502a3b2f47a644831.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5eba8bf0c4a8e49b3fac25832a0b0005.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0e57a13c665af88f326c9890072bf73.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/6/7/5e5c7daa-f6f8-40bc-81bd-7ff4cdc2546b.png?resizew=148)
(3)【定理应用】如图3,在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/71c472fb321d44281f1e6c4da4ecff6e.png)
![](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/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a9d972436cf9555f63b7164b6f7feaa9.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/0ce6e0c28898e278d164e846536b85f4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21037e170bdbb322558e79c40c00b454.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/899f4daf6f7a4d61c16c0f5214461dee.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf3834d7ec7531f3c3c0ce9b286f7a49.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/6/7/61f1766e-d8be-456a-acfc-fad9a18f800d.png?resizew=142)
更新时间:2023-05-21 14:45:06
|
相似题推荐
解答题-证明题
|
困难
(0.15)
【推荐1】如图,在菱形
中,
,
是对角线
上一点,
是线段
延长线上一点且
,连接
.
(1)如图,若
是线段
的中点,连接
,其他条件不变,直接写出线段
与
的数量关系;
![](https://img.xkw.com/dksih/QBM/2021/7/10/2761431860944896/2817273270419456/STEM/b6b97df6-7414-429b-a976-a7be2cf1237b.png)
(2)如图,若
是线段
上任意一点,连接
,其他条件不变,猜想线段
与
的数量关系是什么?并证明你的猜想;
![](https://img.xkw.com/dksih/QBM/2021/7/10/2761431860944896/2817273270419456/STEM/ceb746fe-15de-47fa-a821-70602c61c6ea.png)
(3)如图,若
是线段
延长线上一点,其他条件不变,且
,菱形
的周长为
,直接写出
的长度.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ea4f5eec0addba78f2e0cdfb7ecc59a6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](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/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03687d97d61b4a7cecbb73f2a6604212.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
(1)如图,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://img.xkw.com/dksih/QBM/2021/7/10/2761431860944896/2817273270419456/STEM/b6b97df6-7414-429b-a976-a7be2cf1237b.png)
(2)如图,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://img.xkw.com/dksih/QBM/2021/7/10/2761431860944896/2817273270419456/STEM/ceb746fe-15de-47fa-a821-70602c61c6ea.png)
(3)如图,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7d97dc3b752832906de41447bb58a341.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c7c8630dc73828eec20b778072909fa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2793aa39b517d1a5e7ca2d8243710c8f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d004d2d115b477ade6af7ddb93db0df8.png)
![](https://img.xkw.com/dksih/QBM/2021/7/10/2761431860944896/2817273270419456/STEM/30690354-2616-4dc6-82df-6da8a63ec501.png)
您最近一年使用:0次
解答题-问答题
|
困难
(0.15)
名校
【推荐2】如图1,在
中,
,点
在
上任意一点,连接
.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/3/16/da96f521-2a5b-40d2-acc8-5f49486983ad.png?resizew=454)
(1)如图1,
,D为
中点,
,求
的长;
(2)如图2,若
,
为
的中点,猜想
与
之间的数量关系,并证明你的猜想;
(3)如图3,点P为
边上一动点,连接
,将线段
绕点
按顺时针方向旋转
至
,连接
、
,已知
,
,
,当
周长取得最小值时,请直接写出此时
的面积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/26fdd8e57562ba94e10e7f1d770826d0.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/03902478df1a55bc99703210bccab910.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/3/16/da96f521-2a5b-40d2-acc8-5f49486983ad.png?resizew=454)
(1)如图1,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1682d306c38087d9e6f7efb9cec596a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24ed6782bdaffe2a5ab0fc2cd5191eaa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
(2)如图2,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7de966c316db1013defc56372fcf814e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
(3)如图3,点P为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9fd17a66a2af938c89e46f22e4d893b1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9fd17a66a2af938c89e46f22e4d893b1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c02b54dc6b3e1bb6544f47d4c8743fcf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3525ddc5153fada64eaf14e50b536542.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/84d454c82d9e52747563d47b68099249.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f53330c107f8245290a5a42c3d356acd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0c284ccb6f4ee7a8690013d2ce16e226.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/07140f277a35733d8c97577ccdd4e3ab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/714cc3707bba3bfdb56e251999be8592.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1c8436b6ed51a13c0f4744bc7c6ec457.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1c8436b6ed51a13c0f4744bc7c6ec457.png)
您最近一年使用:0次
解答题-证明题
|
困难
(0.15)
【推荐1】如图,D是等边三角形ABC边BC上一点,DE//AC交AB于点E,B,B′关于直线DE成轴对称,连接B′E,B′D分别交AC于点F,G.
![](https://img.xkw.com/dksih/QBM/2021/7/30/2775130816970752/2780484179779584/STEM/c05af8e3d363403b945b976c2e8b0783.png?resizew=508)
(1)求证:四边形AEDG是平行四边形;
(2)当四边形AEDG是菱形时,求这个菱形的面积与△ABC的面积之比;
(3)当AB=6,DE=2AE时,直接写出四边形AEDG的两条对角线长AD= ,EG= .
![](https://img.xkw.com/dksih/QBM/2021/7/30/2775130816970752/2780484179779584/STEM/c05af8e3d363403b945b976c2e8b0783.png?resizew=508)
(1)求证:四边形AEDG是平行四边形;
(2)当四边形AEDG是菱形时,求这个菱形的面积与△ABC的面积之比;
(3)当AB=6,DE=2AE时,直接写出四边形AEDG的两条对角线长AD= ,EG= .
您最近一年使用:0次
解答题-证明题
|
困难
(0.15)
【推荐2】综合与实践
数学活动课上,老师让同学们结合下述情境,提出一个数学问题:如图1,四边形ABCD是正方形,四边形BEDF是矩形.
![](https://img.xkw.com/dksih/QBM/2022/3/18/2938895613452288/2941110811492352/STEM/5c071b126689411780043ae057daa698.png?resizew=550)
探究展示:
“兴趣小组”提出的问题是:“如图2,连接CE.求证:AE⊥CE.”并展示了如下的证明方法:
证明:如图3,分别连接AC,BD,EF,AF.设AC与BD相交于点O.
∵四边形ABCD是正方形,
∴OA=OC
AC,OB=OD=
BD,且AC=BD.
又∵四边形BEDF是矩形.
∴EF经过点O,
∴OE=OF=
EF,且EF=BD.
∴OE=OF,OA=OC.
∴四边形AECF是平行四边形.(依据1)
∵AC=BD,EF=BD,
∴AC=EF.
∴四边形AECF是矩形.(依据2)
∴∠CEA=90°,即AE⊥CE.
反思交流:
(1)上述证明过程中“依据1”,“依据2”分别是什么?
拓展再探:
(2)“创新小组”受到“兴趣小组”的启发,提出的问题是:“如图4,分别延长AE,FB交于点P,求证:EB=PB.”请你帮助他们写出该问题的证明过程.
(3)“智慧小组”提出的问题是:若∠BAP=30°,AE=
﹣1,求正方形ABCD的面积.请你解决“智慧小组”提出的问题.
数学活动课上,老师让同学们结合下述情境,提出一个数学问题:如图1,四边形ABCD是正方形,四边形BEDF是矩形.
![](https://img.xkw.com/dksih/QBM/2022/3/18/2938895613452288/2941110811492352/STEM/5c071b126689411780043ae057daa698.png?resizew=550)
探究展示:
“兴趣小组”提出的问题是:“如图2,连接CE.求证:AE⊥CE.”并展示了如下的证明方法:
证明:如图3,分别连接AC,BD,EF,AF.设AC与BD相交于点O.
∵四边形ABCD是正方形,
∴OA=OC
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f89eef3148f2d4d09379767b4af69132.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f89eef3148f2d4d09379767b4af69132.png)
又∵四边形BEDF是矩形.
∴EF经过点O,
∴OE=OF=
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f89eef3148f2d4d09379767b4af69132.png)
∴OE=OF,OA=OC.
∴四边形AECF是平行四边形.(依据1)
∵AC=BD,EF=BD,
∴AC=EF.
∴四边形AECF是矩形.(依据2)
∴∠CEA=90°,即AE⊥CE.
反思交流:
(1)上述证明过程中“依据1”,“依据2”分别是什么?
拓展再探:
(2)“创新小组”受到“兴趣小组”的启发,提出的问题是:“如图4,分别延长AE,FB交于点P,求证:EB=PB.”请你帮助他们写出该问题的证明过程.
(3)“智慧小组”提出的问题是:若∠BAP=30°,AE=
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7ffe8515ff6183c1c7775dc6f94bdb8.png)
您最近一年使用:0次
解答题-证明题
|
困难
(0.15)
【推荐1】已知,BD是菱形ABCD的对角线,△DEF是直角三角形,∠EDF=90°,∠DEF=
∠A,连接BE,点G是BE的中点,连接CG、BF.
![](https://img.xkw.com/dksih/QBM/2022/3/6/2930307840114688/2938214688849920/STEM/d35f19f8-5d38-4141-86de-5e68ef4832a5.png?resizew=581)
(1)当∠A=90°时,
①如图1,若△DEF的顶点E落在线段CD上时,请直接写出线段CG与线段BF的数量关系 :
②如图2,当△DEF的顶点E落在线段BD上时,①中线段CG与线段BF的数量关系是否仍然成立?若成立,请给予证明,若不成立,请说明理由.
同学们经过讨论,探究出以下解决问题的思路:
思路一:连接AC,记A与BD相交于点O,AC与BF相交于点M,再利用三角形全等或相似的有关知识来解决问题.
思路二:记AD与EF交于点H,易知H是EF的中点,连接CH,将△CDH绕点C顺时针旋转90°,再利用旋转的性质、三角形全等或相似的有关知识来解决问题.请参考上述思路,完成该问题的解答过程(一种方法即可)
(2)当∠A=120°时,如图3,若△DEF的顶点E落在线段CD上时,请直接写出线段CG与线段BF的数量关系 .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f89eef3148f2d4d09379767b4af69132.png)
![](https://img.xkw.com/dksih/QBM/2022/3/6/2930307840114688/2938214688849920/STEM/d35f19f8-5d38-4141-86de-5e68ef4832a5.png?resizew=581)
(1)当∠A=90°时,
①如图1,若△DEF的顶点E落在线段CD上时,请直接写出线段CG与线段BF的数量关系 :
②如图2,当△DEF的顶点E落在线段BD上时,①中线段CG与线段BF的数量关系是否仍然成立?若成立,请给予证明,若不成立,请说明理由.
同学们经过讨论,探究出以下解决问题的思路:
思路一:连接AC,记A与BD相交于点O,AC与BF相交于点M,再利用三角形全等或相似的有关知识来解决问题.
思路二:记AD与EF交于点H,易知H是EF的中点,连接CH,将△CDH绕点C顺时针旋转90°,再利用旋转的性质、三角形全等或相似的有关知识来解决问题.请参考上述思路,完成该问题的解答过程(一种方法即可)
(2)当∠A=120°时,如图3,若△DEF的顶点E落在线段CD上时,请直接写出线段CG与线段BF的数量关系 .
您最近一年使用:0次
解答题-证明题
|
困难
(0.15)
名校
【推荐2】如图,
为等边三角形,
为平面内任意一点,连接
.
(1)如图1,
在
边上时,将
绕点
逆时针旋转
得到
,连接
,
.直接写出
与
的数量关系为________;直线
与
所夹锐角为________度;
(2)如图2,
在
边上时,将
绕点
逆时针旋转
得到
,连接
交
于
,
为
边的中点,连接
.猜想
与
存在的关系,并证明你的猜想;
(3)如图3,
为
外一点,将
绕点
逆时针旋转
得到
,连接
,取
,
的中点
,
,连接
.试问:
的值是否随图形的旋转而变化?若不变,请求出该值;若变化,请说明理由.
![](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/03902478df1a55bc99703210bccab910.png)
(1)如图1,
![](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/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be6a6301878fed2a01413020b27310a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/11/19/fa6e6069-9a44-4694-8802-985a218305b8.jpg?resizew=126)
(2)如图2,
![](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/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a6c0927afc571a7c966c98192040979e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c63e36329f5e0979f5ee776ac5d06327.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c63e36329f5e0979f5ee776ac5d06327.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/11/19/b2949bb9-4549-45ae-ad73-07b366475bb2.jpg?resizew=146)
(3)如图3,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be6a6301878fed2a01413020b27310a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2044b01c3e9f0bdece72ad17bdfd886d.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/11/19/8c6bc7e1-104c-4719-9004-047dcc13d14b.jpg?resizew=129)
您最近一年使用:0次
解答题-问答题
|
困难
(0.15)
解题方法
【推荐1】如图,在平面直角坐标系中,二次函数
的图象与x轴交于点
,与y轴交于点C,其对称轴与x轴交于点D.
(2)若点E是线段
上的一点,过点E作x轴的垂线,垂足为F,且
,求点E的坐标;
(3)若P为y轴上的一个动点,连接
,直接写出
的最小值;
(4)若点P是抛物线对称轴上的一个动点,连接
,设点P的纵坐标为t,当
不小于
时,求t的取值范围.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d8de071a9c22c96a59b172d76c127e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/869244d5d6d5361c09a5f016cf67a5b2.png)
(2)若点E是线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8bfdbf5dc04d1786c7db94d1e81a7188.png)
(3)若P为y轴上的一个动点,连接
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0629ce42392a7fe9be21d25c39c3e64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fd7ff40453334bdfa2d637e22843beb2.png)
(4)若点P是抛物线对称轴上的一个动点,连接
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a1443bfe022f648f813fb1e15b2d78b6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac3c1375c64dceef45846308a418cf7f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be6a6301878fed2a01413020b27310a5.png)
您最近一年使用:0次
解答题-问答题
|
困难
(0.15)
【推荐2】如图1,在平面直角坐标系中,抛物线
、
、
为常数且
经过原点
和
,且对称轴为直线![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d599059e6b2c918ab15ee22611b6962.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/15/3218dddd-3e16-4861-83ad-d2bc43cf54fa.png?resizew=263)
(1)求抛物线的函数表达式;
(2)在抛物线上是否存在点
,使
中
边上的高为
?若存在,求出点
的坐标;若不存在,请说明理由;
(3)如图2,设抛物线与
轴的另一交点为
,点
在抛物线上,满足
,若
是直线
下方的抛物线上且到
的距离最大的点,试求出所有满足
的点
的坐标(点
、
、
分别与点
、
、
对应).
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/729358c8511d239e3c26e00fa4711bb4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c94bb12cee76221e13f9ef955b0aab1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/071a7e733d466949ac935b4b8ee8d183.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f28b08682efa2692b052f64fe1448fce.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c78b8c8353ed5d9144e451c56afa9607.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d599059e6b2c918ab15ee22611b6962.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/15/3218dddd-3e16-4861-83ad-d2bc43cf54fa.png?resizew=263)
(1)求抛物线的函数表达式;
(2)在抛物线上是否存在点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3bdfe807af9e6573270b2e10cca230eb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b90e0f35eda1a729fed485f83da5ea9d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/95bacae35b6e16a0a33c2bdc6bc07df7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
(3)如图2,设抛物线与
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e31d35479633b046c1bfc229c15b2be3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b90e0f35eda1a729fed485f83da5ea9d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b90e0f35eda1a729fed485f83da5ea9d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/142bd2d05e7d6cd47a62c0d595f7afd3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
您最近一年使用:0次