【问题提出】如图①,在
中,若
,
,求
边上的中线
的取值范围.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/5/16/5efe93f2-ea42-49f3-bcce-fe62dee7d83d.png?resizew=488)
【问题解决】解决此问题可以用如下方法:延长
到点
,使
,再连接
(或将
绕着点
逆时针旋转
得到
),把
、
、
集中在
中,利用三角形三边的关系即可判断.由此得出中线
的取值范围是________.
【应用】如图②,在
中,
为边
的中点,已知
,
,
,求
的长.
【拓展】如图③,在
中,
,点
是边
的中点,点
在边
上,过点
作
交边
于点
,连接
.已知
,
,直接写出
的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54275b7e571660d0a9e0370fbfe5050b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a8a7b5adfcac0f46a4cd19da4ebb4a2b.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/2023/5/16/5efe93f2-ea42-49f3-bcce-fe62dee7d83d.png?resizew=488)
【问题解决】解决此问题可以用如下方法:延长
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0ad98ad714864041a632ca949308e417.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7ac451db3443cabb204f96c31fd4a02e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bfe639eab78eafd2d40ea70aa5d3f21d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b96715995549e5e48494101570bb3bb8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e97392ff60fac8a261c6eab71bba028b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e742966e3711cfa53dce04022acf4bcc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
【应用】如图②,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/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9f08273d339dc5ddbb89aa67bb8205e6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d70dc2c20619a4fc12a0cfda59af5b69.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09d27bd71d79cb19eb554175e4ef0867.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
【拓展】如图③,在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8f89deb952f57f4b3fa4887b098b7b91.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/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c175c239742c7ba8fd67a6d5f99cb1b3.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/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1d2231c7a2875ab6d423dff3ead4069.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/56512504254ab7f574a717dd6830fb33.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
22-23八年级下·山西临汾·期中 查看更多[4]
山西省临汾市霍州市2022-2023学年八年级下学期4月期中数学试题山西省大同市第一中学校北校2022--2023学年八年级下学期素养评估(5月月考)数学试题(已下线)专题1.17 构造直角三角形解决问题(分层练习)-2023-2024学年八年级数学上册基础知识专项突破讲与练(北师大版)(已下线)专题3.17 构造直角三角形解决问题-2023-2024学年八年级数学上册基础知识专项突破讲与练(苏科版)
更新时间:2023-05-12 15:43:42
|
相似题推荐
解答题-计算题
|
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名校
【推荐1】先化简,再求值:
,其中b与
构成
的三边,且b为整数.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e672bbc334b6c4ab4da8307943a81cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/90fb6e8a63763cbece1cd5b056824f3a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
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【推荐2】【阅读材料】
配方法是数学中一种重要的思想方法.它是指将一个式子或一个式子的某一部分通过恒等变形化为完全平方或几个完全平方式的和的方法.这种方法常被用到代数式的变形中,并结合非负数的意义来解决一些问题.
①用配方法分解因式
例1:分解因式
.
解:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f2caf24b3aba58e2b83928540919be0f.png)
.
②用配方法求值
例2:已知
求
的值.
解:原方程可化为,
,即
,
,
,
,
,
.
③用配方法确定范围
例3:
,利用配方法求M的最小值.
解:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d9d3c9ece403349d4136c53d077a84e1.png)
,
当
时,M有最小值
.
请根据上述材料解决下列问题:
(1)用配方法分解因式
;
(2)已知
的三边长a,b,c,且满足
,求边c的取值范围;
(3)已知
,
.试比较P,Q的大小.
配方法是数学中一种重要的思想方法.它是指将一个式子或一个式子的某一部分通过恒等变形化为完全平方或几个完全平方式的和的方法.这种方法常被用到代数式的变形中,并结合非负数的意义来解决一些问题.
①用配方法分解因式
例1:分解因式
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bc8858c120c50b64f7071fc55316dd43.png)
解:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f2caf24b3aba58e2b83928540919be0f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6d785c3826e4d36ae8ae8eafb59a2c4b.png)
②用配方法求值
例2:已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/af860678725c6ea1c72d33416d436fde.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b88584cf1df43e28d03592c7998b1653.png)
解:原方程可化为,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/19fd4cdb2e9c6b91fb0bbe5f88cfc7d7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e22fd6ae0b6745bffd6f656e04027162.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/39309b9323c68c0df08eae45d9bdc93c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7ce957370690673e716e11ea635b4921.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/452f1a5f8279877f0902cb15a8f24a9d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1d0aa9412dd7caf42cc71520e282328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d73f309999bad1f1a4d75e9f1e705f0.png)
③用配方法确定范围
例3:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d33029c930d0bf513a8ecaf05e5d6776.png)
解:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d9d3c9ece403349d4136c53d077a84e1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/39309b9323c68c0df08eae45d9bdc93c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2de0d10ef8b748d4531250c37c5d3f9e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b384412acba251d87902ab928902f16.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/274a9dc37509f01c2606fb3086a46f4f.png)
请根据上述材料解决下列问题:
(1)用配方法分解因式
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1c083d7edb1c6a5a93df2d4531a255f.png)
(2)已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c89bb942014b503db17aaa4bc4db4c0a.png)
(3)已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a40a743e3f046c85fa024e97a3784f9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1dc555174cd087f5d2bfd04886af79e.png)
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解答题-证明题
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适中
(0.65)
名校
【推荐1】在△ABC中,D为BC边中点,DM,ND分别是∠ADB,∠ADC的内角平分线.
(1)请比较MN与BM+CN的大小关系,并证明;
(2)当∠BAC=90°时,BM=2,CN=
,求MN的长度.
(1)请比较MN与BM+CN的大小关系,并证明;
(2)当∠BAC=90°时,BM=2,CN=
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2967337e3fcb228dded64ab0c41a17e0.png)
![](https://img.xkw.com/dksih/QBM/2021/7/16/2765221694840832/2776635127169024/STEM/a4c6adfe379c48639a119982cd99c483.png?resizew=215)
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解题方法
【推荐2】问题背景:“半角模型”问题.如图1,在四边形
中,
,
,
,点E,F分别是
上的点,且
,连接
,探究线段
之间的数量关系.
到点G.使
.连结
,先证明
,再证明
,从而得出结论:_____________;
(2)拓展延伸:如图2,在四边形
中,
,
,E、F分别是边
上的点,且
,请问(1)中的结论是否仍然成立?若成立,请写出证明过程,若不成立,请说明理由.
(3)尝试应用:如图3,在四边形
中,
,
,E、F分别是边
延长线上的点,且
,请探究线段
具有怎样的数量关系,并证明.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e735a28578ba191da6d4f3b0f8e8729.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9eee296a7d9fba487f1485c61580196f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21eb847a1722ed6e10e23c59d53fe7d3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0ced324a15510f9cf7518d8c277c6b50.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4a9eb456c912e01458c19b06e83a5c9d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a45bb0e736a231e0179772a5c036124.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/00bab17635a999236e8d2e35017a208d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bc180eda08edfb6d54eb04da7741f099.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/77a7e4a6765ce78b05ee97764771e01f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fa02cdeb873de61531af157f5773a479.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b5d350426e2929ebe5841e0a40f594a8.png)
(2)拓展延伸:如图2,在四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e735a28578ba191da6d4f3b0f8e8729.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/173904239da66b7bef7cb1d997cc40ed.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0ced324a15510f9cf7518d8c277c6b50.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a6aef04eceb608a7a2cfc3e566f9e8b.png)
(3)尝试应用:如图3,在四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e735a28578ba191da6d4f3b0f8e8729.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8bd602a957d7f6d0940f79a1121b78c6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0ced324a15510f9cf7518d8c277c6b50.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a6aef04eceb608a7a2cfc3e566f9e8b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a45bb0e736a231e0179772a5c036124.png)
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【推荐1】矩形在平面直角坐标系中的位置如图所示,已知
,点
在
轴上,点
在
轴上,
是对角线
上一动点(不与原点重合),连接
,过点
作
,交
轴于点
.
(1)直接写出
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/16ca90e8a784f990c4097eec9219908d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c26a46e7879436d532af3f4b6e258a81.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/35024a9f27d0d4e5fe0aea1667003de8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
(3)在运动过程中,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eb8490cab76a1a6e5cb35de8535be9be.png)
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【推荐2】)△ABC中,AB=AC=2,BC边上有100个不同的点p1,p2,…p100;记
,求
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a756290840968f25c52019506014e90f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1185224f8ad85fa9b59c299e2c18c621.png)
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