如图,一农户要建一个矩形猪舍,猪舍的一边利用长为
的住房墙,另外三边用
长的建筑材料围成,为方便进出,在垂直于住房墙的一边留一个
宽的门.
?
(2)猪舍面积最大时,所围矩形猪舍的长、宽分别为多少?
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e978c77cb0d7eff794447241e9829867.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/146ea9ed5176797da555a70bbe9602c4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1f328ba89c0a92a4447788b65571f7aa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6ce8a83405c52b2984f4ac323369d3fd.png)
(2)猪舍面积最大时,所围矩形猪舍的长、宽分别为多少?
更新时间:2024-04-13 13:53:36
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【推荐1】阅读探究:任意给定一个矩形
,是否存在另一个矩形
,它的周长和面积分别是已知矩形周长和面积的一半
(1)当已知矩形
的相邻两边的长分别为6和1时,小亮同学是这样研究的:设所求矩形的相邻两边的长分别是
和
,由题意得方程组
,消去
,化简
,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/16f3d198e76391779fa3badc848c8ac8.png)
,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2de0d10ef8b748d4531250c37c5d3f9e.png)
________,
________,所以存在满足要求的矩形;
(2)如果已知矩形
的相邻两边的长分别为2和1,请你仿照小亮的方法研究是否存在满足要求的矩形
;
(3)如果矩形
的相邻两边的长分别为
和
,请你研究满足什么条件时,矩形
存在.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
(1)当已知矩形
![](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/d053b14c8588eee2acbbe44fc37a6886.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03bb1fb5e537aad60dd15175934e4b7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d053b14c8588eee2acbbe44fc37a6886.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a89a936252e950e3153b693e48d6371b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/16f3d198e76391779fa3badc848c8ac8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8514fbd74a7bc1169c5b6893d4b7faa2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2de0d10ef8b748d4531250c37c5d3f9e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e92f14fb20f920f88dcad2ccd1d53f2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15dad5a12f34bed0da0de93beae0eaa4.png)
(2)如果已知矩形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
(3)如果矩形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
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名校
【推荐2】阅读材料:200多年前,数学王子高斯用他独特的方法快速计算出
的值.我们从这个算法中受到启发,用下面方法计算数列1,2,3,…,n,…的前n项和:
由![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/3/5d47a5ec-0a2f-43a7-be58-575304f4658b.png?resizew=274)
可知
.
应用以上材料解决下面问题:
(1)有一个三角点阵(如图),从上向下数有无数多行,其中第一行有1个点,第二行有2个点…,第n行有n个点…,若该三角点阵前n行的点数和为325,求n的值.
(2)在第一问的三角点阵图形中,前n行的点数和能是900吗?如果能,求出n;如果不能,说明理由.
(3)如果把上图中的三角点阵中各行的点数依次换为3,6,9,…,3n,…,前n行的点数和能是900吗?如果能,求出n;如果不能,说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ddce9c83d496f0925324cc2ee190553a.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/3/d602293a-5829-4d86-be51-9ab01c87f20a.png?resizew=163)
由
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/3/5d47a5ec-0a2f-43a7-be58-575304f4658b.png?resizew=274)
可知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/17327407594d2f79f6a0897595afe430.png)
应用以上材料解决下面问题:
(1)有一个三角点阵(如图),从上向下数有无数多行,其中第一行有1个点,第二行有2个点…,第n行有n个点…,若该三角点阵前n行的点数和为325,求n的值.
(2)在第一问的三角点阵图形中,前n行的点数和能是900吗?如果能,求出n;如果不能,说明理由.
(3)如果把上图中的三角点阵中各行的点数依次换为3,6,9,…,3n,…,前n行的点数和能是900吗?如果能,求出n;如果不能,说明理由.
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【推荐1】如图,抛物线
与
轴相交于
、
两点,与
轴相交于点
,点
是直线
下方抛物线上一点,过点
作
轴的平行线,与直线
相交于点
.
求直线
的解析式;
当线段
的长度最大时,求点
的坐标.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/680cdc840f06bbd6c80764263de665fb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d053b14c8588eee2acbbe44fc37a6886.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
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![](https://img.xkw.com/dksih/QBM/2018/10/30/2064614113583104/2067505917304832/STEM/ca3856dd1792490a8fd8d783fea2b25d.png?resizew=103)
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【推荐2】如图,有长为30米的篱笆,围成中间隔有一道篱笆的长方形的花圃,且花圃的长可借用一段墙体.(墙体的最大可用长度为14米)设
,长方形
的面积为S
.
![](https://img.xkw.com/dksih/QBM/2020/3/25/2427097726877696/2427352864497666/STEM/c546c2d5a3c84627a9643cfc6f64b5b2.png?resizew=193)
(1)求
与
的函数关系式;
(2)如果要围成面积为72平方米的花圃,
的长是多少米?
(3)能围成面积比72平方米更大的花圃吗?如果能,请求出最大面积,并说明围法;如果不能,请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fa7d86ba5d8266e2050cc96dfb8fdcb0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
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(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf231f8f86fb922df4ca0c87f044cec3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
(2)如果要围成面积为72平方米的花圃,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
(3)能围成面积比72平方米更大的花圃吗?如果能,请求出最大面积,并说明围法;如果不能,请说明理由.
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