1 . 阅读下列文字,体会其中的数学思想方法:善于思考的小高同学在解关于m,n的方程组
时,把
,
分别看成一个整体,令
,
,原方程组化为
解得
∴
解得
∴原方程组的解为
.
这种把某个式子看成一个整体,用一个字母代替它的解方程组的方法叫做“换元法”.
(1)应用:已知方程组
的解是
则关于m,n的二元一次方程组
的解是______.
(2)迁移:请用换元法解方程组:
;
(3)拓展:若关于x,y的二元一次方程组
的解是
求关于m,n的方程组
的解.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/949491acdcbd0d70675f900315df9072.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/72de735ca49a35422bed8c0509b2ddb5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/19c0cad05922d240afa9861ff4316a17.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/108ceebceb65f03525fbb1822072f041.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/84e1c7efb9604f006520344e586439c2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85d9e29f8752eb6967cc43860a85f564.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/53d85fb484e0b493a3077ae5b82b27f2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/69666a33305d07ca55065a4ed92a397d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40002b224c3ea95c98145eba589887f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40002b224c3ea95c98145eba589887f.png)
这种把某个式子看成一个整体,用一个字母代替它的解方程组的方法叫做“换元法”.
(1)应用:已知方程组
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f428c33f91bf0f27381ab5058b4187aa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c1067fa649d8713d859aaf9ea6404a09.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61826aa7ba29eaceadcb546f207e9d86.png)
(2)迁移:请用换元法解方程组:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd77b7a6ab294691167e0622a048f782.png)
(3)拓展:若关于x,y的二元一次方程组
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a65bd6cdc598a67059dc4293a1694dc0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/148c60110e3d2f8079be96fccdc58598.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0334d791eb41530cdc74d6677cfa922f.png)
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2 . 数与形是数学中的两个最古老,也是最基本的研究对象.数与形也是有联系的,这种联系称为“数形结合”.利用“数形结合”思想可以直观地帮助我们解决一些数学验证或运算.
(1)我国是最早了解勾股定理的国家之一,该定理阐明了直角三角形的三边关系.请你利用如图对勾股定理(即下列命题)进行验证,从中体会“数形结合”的思想:
和
中,
,(点
,
,
在一条直线上),
,
,
.
证明:
;
(2)请利用“数形结合”思想,画图并推算出
的结果.
(1)我国是最早了解勾股定理的国家之一,该定理阐明了直角三角形的三边关系.请你利用如图对勾股定理(即下列命题)进行验证,从中体会“数形结合”的思想:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd967903ed5a6f640a5b801ec8be0070.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c2598f844644c4245eb226ecca57ee4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8011c139632bfc21aa20bb68657d8464.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8364fb24b3eb48ecca9b623a41c6358d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a4225465934b192802eb75bb50680724.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f599b5bfb98c1dabb04757b9751cdc16.png)
证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3133ef62aad6bdd6637140620f068fad.png)
(2)请利用“数形结合”思想,画图并推算出
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a5960b5ba8bc7d4d138f597bc64db614.png)
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3 . 勾股定理是平面几何中一个极为重要的定理,世界上各个文明古国都对勾股定理的发现和研究作出过贡献.特别是定理的证明,据说方法有
余种.其中我国汉代的赵爽在注解《周髀算经》时给出了证明.请你用下面弦图(由四个全等的直角三角形围成的)证明勾股定理:
如果直角三角形
的两条直角边长分别为
,斜边长为
,那么
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ba602bfa3a3ffb4fb43dc0f704a7f7d.png)
如果直角三角形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/632244ea6931507f8656e1cc3437d392.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/071a7e733d466949ac935b4b8ee8d183.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3133ef62aad6bdd6637140620f068fad.png)
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名校
4 . 在
的高
、
交于点
,
.
;
(2)如图1,求
的度数;
(3)如图2,延长
到点
,过点
作
的垂线交
的延长线于点
,当
时,探究线段
、
、
的数量关系,并证明你的结论.
![](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/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b7bd0846e377e291fc3483792e2d599a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf42e334e75105daba4930d11e2b3c55.png)
(2)如图1,求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d39b8d91afc34e4a9b0fdbb6bafb9087.png)
(3)如图2,延长
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7dea2ae9d515f9ab351ad72306b776ee.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73465a1f9aa03481295bf6bd3c6903ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c3f45f04e03c0de76773087ad3ab0c93.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/abf80148409afb32ced0b4f59f1ba709.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bcdae78f4d3b8d8213ac3ac9a9567eb5.png)
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5 . 2023年暑假,我校顺利完成了大门改造,新大门气势磅礴,宏伟壮观,彰显着非凡的尊贵气息.小蓝为了测量大门的高度
,采取了以下方法:在校门口
点处测得大门顶
点处的仰角为
,步行过马路后,马路宽度约为
米,在马路对面的
点处测得大门顶
点处的仰角为
,已知小蓝的眼睛距离地面高度为
米,则大门高度
约为_______ 米.(仰角:是从低处向高处观察目标时,视线与水平线所形成的角度.结果保留
位小数,参考数据:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7ffe8515ff6183c1c7775dc6f94bdb8.png)
)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b79dd200766db27fb90d6bd1992cf658.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b342d5cb6dd1c84a82f6aca68ed829c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/45e61680ffc6f940bd5b8afda3ae9c59.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3c030b25575d683af91c06e6a3e4f463.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7b10b97941e03aad713a0d9ed503f326.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b79dd200766db27fb90d6bd1992cf658.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7ffe8515ff6183c1c7775dc6f94bdb8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e98cacd69d1a633140bde1db96f40ff.png)
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6 . 数学课上,老师在黑板上画出如图所示的三角形,并要求学生添加一个条件,使得
,下面四位同学给出的条件中有一个无法证明这个结论,则这位同学是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1d021981c03e75b1a246d899dcc64656.png)
亮亮 | 天天 | 花花 | 丽丽 |
![]() | ![]() | ![]() | ![]() |
A.亮亮 | B.天天 | C.花花 | D.丽丽 |
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昨日更新
|
51次组卷
|
2卷引用:宁夏银川十中、十五中2023-2024学年七年级下学期期中数学试题
7 . 科技点亮未来,创新改变生活.某校七年级
班同学参加了学校科技节比赛,制作了如图
所示航天火箭模型,为了向全校同学宣传自己的科技作品,用
板制作了如图
所示的宣传版画,它是由一个三角形,两个梯形组成,已知
板(阴影部分)的尺寸如图
所示.
的代数式表示图
的
板模型的总面积(结果需化简);
(2)若
,
,求
板总面积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdaa19de263700a15fcf213d64a8cd57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdaa19de263700a15fcf213d64a8cd57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb5529046d232de846352a439d991439.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb5529046d232de846352a439d991439.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/663a61ad241d5d874c9a9362f0ee917c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb5529046d232de846352a439d991439.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a8641de131e86041bb4cee948569cdc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1b4c95465c295bca4c5cb2bd9ad0c7c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb5529046d232de846352a439d991439.png)
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8 . 计算
(1)
;
(2)
;
(3)
(运用整式乘法公式简便计算);
(4)
;
(5)
(运用整式乘法公式简便计算).
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a1e3a3d1f01ebe6cdf3d46d2797d07e2.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ba150708c3f9dbf96843b7cfb053099.png)
(3)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8d47668c38a31b54a7b3556b2262a0f9.png)
(4)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f32206a8684a350b9b3fedac4470698.png)
(5)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7703ab8407aba8b508a2136a11b3022b.png)
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9 . 如图,已知
,
相交于点
,
,
,
分别在
、
、
上,且
,
,
,求证:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.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/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73465a1f9aa03481295bf6bd3c6903ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/948b0f3935e54d5425b889715f80cb1f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0e53497af8899cb299d762f1a4f46a55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0690d4a5a87b9bdb8da03a9e83c7fb55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd80e6ab9d2a274ad02d8ef27df30ddf.png)
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10 . 如图,在平面直角坐标系中,已知
,
两点,其中
、
、
满足等式
.动点
从点
出发,沿折线
以每秒2个单位长度的速度向终点
运动.设点
运动时间为
,当四边形
为正方形时,解答下列问题.
__________,
__________,
__________;当点
在线段
上时,
的长度为___________.(用含
的代数式表示)
(2)当
时,求三角形
的面积.
(3)当
时,三角形
的面积为__________.
(4)当
时,直接写出
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e0790154c378e41d4ac3c174eb9caba.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/97b6c76385562bdae891434052722481.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.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/ef8ecc51c18cdaa3de52f1446e817b17.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/4b96137f2cb4a079c6fc0c5988b2b6cc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c60660003b3847e80ab50a560171ae1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c63411dce0b6059061c75ba96f22bbef.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/503166d70d152eb0617a4c050cb50d1c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/656299e934c30765283518092dc665d4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a78185de2a4c4775e0922292b64d69f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9fd17a66a2af938c89e46f22e4d893b1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b650820d7bed48ed67a2869ad8c65ff1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/30f457418e6a7e21f0ed0bf490a3709c.png)
(3)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d599059e6b2c918ab15ee22611b6962.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/30f457418e6a7e21f0ed0bf490a3709c.png)
(4)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd621db8b22ac8335c214807f587d2d7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
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