如图,
中,
,高
,矩形
的一边
在
边上,E、F两点分别在
上,
交
于点H,设
.
(1)用含有x的代数式表示
的长;
(2)当x为何值时,矩形
的面积最大?并求其最大值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57ebb33adb2310a6e03918761e68204a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/04ee826937d2add7a93aaa1422f8b736.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e68d0260fb6cf6ffb9a63ab54f312012.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/56f6927cc2a930203ac34366383e76ef.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f0d54431bbb28ebd98db5c1dc6083a75.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0124d4c22e17a6b719cf2d0f0b305e4e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/10/7/0b15e3fd-3831-4cac-8f12-6156800367a9.png?resizew=183)
(1)用含有x的代数式表示
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c7e4fa04825ac7d071968056322d88be.png)
(2)当x为何值时,矩形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e68d0260fb6cf6ffb9a63ab54f312012.png)
更新时间:2023-10-04 17:15:27
|
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解答题-作图题
|
适中
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【推荐1】数学活动课上,老师提出问题:如图,
有一张长4dm,宽3dm的长方形纸板,在纸板的四个角裁去四个相同的小正方形,然后把四边折起来,做成一个无盖的盒子,问小正方形的边长为多少时,盒子的体积最大.
下面是探究过程,请补充完整:
(1)设小正方形的边长为xdm,体积为ydm3,根据长方体的体积公式得到y和x的关系式: ;
(2)确定自变量x的取值范围是 ;
(3)列出y与x的几组对应值.
(说明:表格中相关数值保留一位小数)
(4)在下面的平
面直角坐标系xOy中,描出以补全后的表中各对对应值为坐标的点,画出该函数的图象;
(5)结合画出的函数图象,解决问题:当小正方形的边长约为 dm时,盒子的体积最大,最大值约为 dm3.
![](https://img.xkw.com/dksih/QBM/2018/9/13/2031525394284544/2033501799956481/STEM/9ca2f4aababe40beb63a1156c3c0f619.png?resizew=3)
下面是探究过程,请补充完整:
(1)设小正方形的边长为xdm,体积为ydm3,根据长方体的体积公式得到y和x的关系式: ;
(2)确定自变量x的取值范围是 ;
(3)列出y与x的几组对应值.
x/dm | … |
|
|
|
|
| 1 |
| … | |||
y/dm3 | … | 1.3 | 2.2 | 2.7 | 3.0 | 2.8 | 2.5 | 1.5 | 0.9 | … |
(4)在下面的平
![](https://img.xkw.com/dksih/QBM/2018/9/13/2031525394284544/2033501799956481/STEM/9ca2f4aababe40beb63a1156c3c0f619.png?resizew=3)
(5)结合画出的函数图象,解决问题:当小正方形的边长约为 dm时,盒子的体积最大,最大值约为 dm3.
![](https://img.xkw.com/dksih/QBM/2018/9/13/2031525394284544/2033501799956481/STEM/3e88d5a880ff4942aa792e042c794e21.png?resizew=193)
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解答题-问答题
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适中
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【推荐2】为了节省材料,某公司利用岸堤
(岸堤足够长)为一边,用总长为80米的材料围成一个由三块面积相等的小长方形组成的长方形
区域,如下两图,为两个不同的方案.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/21/d2333506-ecea-43be-8a9f-daf7e9e54998.png?resizew=272)
(1)如图1,若
米,求长方形
的面积S(用含
的代数式表示);
(2)如图2,①
与
的数量关系是 ;
②若
米,求长方形
的面积S(用含
的代数式表示),并求S的最大值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/21/d2333506-ecea-43be-8a9f-daf7e9e54998.png?resizew=272)
(1)如图1,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8e781a2489271bfd1597cba1bb6f5887.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
(2)如图2,①
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
②若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/202a87b61bf384f9ac48935fe495cc9b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
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解答题-问答题
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适中
(0.65)
【推荐1】如图,Rt△ABO的直角顶点O为坐标原点,∠OAB=30°,点A在反比例函数
(x>0)的图象上,点B在反比例函数
(x<0)的图象上.
(1)当OA是第一象限的角平分线时,求点A的坐标.
(2)点A在运动过程中,k的值是否发生变化?如果变化,请说明理由,如果不变,请求出k的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/498bcfd1aac03057dcd0adef2dd113a3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/07854693dd2e33f66030d6106eb6e0ee.png)
(1)当OA是第一象限的角平分线时,求点A的坐标.
(2)点A在运动过程中,k的值是否发生变化?如果变化,请说明理由,如果不变,请求出k的值.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/11/689d4b47-672d-4dbb-b0bf-238320821c5e.png?resizew=191)
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解答题-证明题
|
适中
(0.65)
【推荐2】在
中,
,
,直线
经过点
,过点
、
分别作
的垂线,垂足分别为点
、
.
如图①,若直线
,
,分别求出线段
、
和
的长;
(2)规律探究:
如图②,若直线
从图①状态开始绕点
顺时针旋转α(
),与线段
相交于点
,请再探线段
、
和
的数量关系并说明理由;
(3)尝试应用:
在图②中,延长线段
交线段
于点
,若
,
,求
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e428e7a09732be85c1224e9c8f6a71c5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a717e6dc97553f48fcdbc36247884efc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6ab41054fa9ce51b68e78d9c0cf398d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f85fca60a11e1af2bf50138d0e3fe62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.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/0f85fca60a11e1af2bf50138d0e3fe62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
如图①,若直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60a1eb9d682e2bd181f3b0f5115160b1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/98e486a1aad96167ff62f6fb5136e0bb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b3182db896bc2462331796e2a6108363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a6b41d4070854edfaa24071137b314cb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1a6c6e7c025362c46a64a8956761f08e.png)
(2)规律探究:
如图②,若直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f85fca60a11e1af2bf50138d0e3fe62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cca2ac57e8b93eca23063cb0a3b701c0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/764509115979e9958101808383672ec0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73465a1f9aa03481295bf6bd3c6903ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b3182db896bc2462331796e2a6108363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a6b41d4070854edfaa24071137b314cb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1a6c6e7c025362c46a64a8956761f08e.png)
(3)尝试应用:
在图②中,延长线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b3182db896bc2462331796e2a6108363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1a9c6a736e6eac98a676fa3232db5a5.png)
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