如图,有长为24米的篱笆,一面利用墙(墙的最大可用长度为12米),围成中间隔有一道篱笆的长方形花圃.
的长为x米,则围成的矩形
的面积为
,请用含x的代数式来表示y,并写出x的取值范围;
(2)若围成花圃的面积为36平方米,请求出
的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/67d822262ff00915910e5b87d81ad1ba.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/65a20728e9a9e3018723f2a86f24f332.png)
(2)若围成花圃的面积为36平方米,请求出
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
更新时间:2024-05-14 12:11:21
|
相似题推荐
解答题-问答题
|
适中
(0.65)
名校
【推荐1】在美化校园的活动中,某兴趣小组想借助如图所示的直角墙(DM长为15米,DN长为20米),用28m长的篱笆围成了一个面积为192m
的长方形花园ABCD(篱笆只围AB,BC两边).求篱笆BC长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3a0a8fb0c81d853a0195d47877b5540a.png)
![](https://img.xkw.com/dksih/QBM/2020/1/2/2368432824885248/2369112434114560/STEM/9ab73a12f7944b80bbcdd09496a00f8d.png?resizew=131)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
【推荐2】将一条长为
的铁丝剪成两段,并以每一段铁丝的长度为周长做成一个正方形.
(1)如果要使这两个正方形的面积之和等于
,那么这段铁丝剪成两段后的长度分别是多少?
(2)两个正方形的面积之和可能等于
吗?若能,求出两段铁丝的长度;若不能,请说明理由.
(3)这两个正方形的面积之和的最小值是多少?
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a3323b82789490e2ef8d3af410c0ffa4.png)
(1)如果要使这两个正方形的面积之和等于
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f19642ca60ff04094d30281f991a60c1.png)
(2)两个正方形的面积之和可能等于
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/997c707d10bb903d971de9ae1b337530.png)
(3)这两个正方形的面积之和的最小值是多少?
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
【推荐1】如图,在边长为
的正方形
各边上取点
,
,
,
(可与
,
,
,
重合),使得四边形
为正方形.设
为
,正方形
的面积为
.
(1)
关于
的函数表达式是________,自变量
的取值范围是________;
(2)在下面的平面直角坐标系
中,画出(1)中函数的图象;
(3)当
________
时,正方形
面积有最小值________
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/095ab4a92bf822e175d370e6d0c8a730.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.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/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/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/611f100dcfa7803db6eb233e2e7f2dab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ee3160fce05b551569b8c7b5de6dd8b6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/611f100dcfa7803db6eb233e2e7f2dab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4d740004cfdade4c185f722dadc27e15.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/2/1/65ce919d-8ed5-4359-862c-d6a1d05932f2.png?resizew=398)
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d053b14c8588eee2acbbe44fc37a6886.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
(2)在下面的平面直角坐标系
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7ee31829d0d4d5f779a957d7df8058ab.png)
(3)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4ec0618ae3a4fde6d6220010af229b9a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9efa9fbcfb9595e2f031aa691db4564b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/611f100dcfa7803db6eb233e2e7f2dab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/88ce13774b09ff2edddaf21a072cf60a.png)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
名校
【推荐2】某牧场准备利用现成的一堵“7”字型的墙面(如图中粗线
表示墙面,已知
,
米,
米)和总长为36米的篱笆围建一个“日”形的饲养场
(细线表示篱笆,饲养场中间
也是用篱笆隔开),如图,点
可能在线段
上,也可能在线段
的延长线上.
![](https://img.xkw.com/dksih/QBM/2021/6/8/2738445191487488/2743792689184768/STEM/801c1022-e0d8-4a4f-8dfb-ef00a950794e.png?resizew=282)
(1)当点
在线段
上时,
①设
的长为
米,则
______米(用含
的代数式表示);
②若要求所围成的饲养场
的面积为66平方米,求饲养场的宽
;
(2)饲养场的宽
为多少米时,饲养场
的面积最大?最大面积为多少平方米?
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0cc6293cfedec30b124ece908c4c438.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/080db3af81b29ed10144a1c2e2a4fb8a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/efc6e4b936d7a800e839a30c3839574d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/65fc998d33cdf37c272f79cfd64b7b99.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f84f169e50dc59d4f7a8e1e36f5c847.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e42887d9bf31c1dd99f13c39e63c9ab9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://img.xkw.com/dksih/QBM/2021/6/8/2738445191487488/2743792689184768/STEM/801c1022-e0d8-4a4f-8dfb-ef00a950794e.png?resizew=282)
(1)当点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
①设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/404728d0ea2699c71e674f30dd984abd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
②若要求所围成的饲养场
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f84f169e50dc59d4f7a8e1e36f5c847.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
(2)饲养场的宽
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f84f169e50dc59d4f7a8e1e36f5c847.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
【推荐3】阅读材料:
①对于任意实数a和b,都有
,∴
,得到
,当且仅当
时,等号成立.
②任意一个非负实数都可写成一个数的平方的形式.即:如果a≥0,则
.如:
等.
例:①用配方法求代数式
的最小值.
②已知
,求证:
.
①解:由题意得:
,
∵
,且当
时,
,
∴
,
∴当
时,代数式
的最小值为:
;
②证明:∵
,∴![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5995e8774decd9d4fe698c109a4acdc0.png)
∴
,当且仅当
,即
时,等号成立.
请解答下列问题:某园艺公司准备围建一个矩形花圃,其中一边靠墙(墙足够长),另外三边用篱笆围成(如图所示).设垂直于墙的一边长为x米.
![](https://img.xkw.com/dksih/QBM/2022/10/12/3085898821697536/3086626708406272/STEM/5637c5a1db474a71a154c4077d63e4fe.png?resizew=147)
(1)若所用的篱笆长为36米,那么:
①当花圃的面积为144平方米时,垂直于墙的一边的长为多少米?
②设花圃的面积为S米
,求当垂直于墙的一边的长为多少米时,这个花圃的面积最大?并求出这个最大面积;
(2)若要围成面积为200平方米的花圃,需要用的篱笆最少是多少米?
①对于任意实数a和b,都有
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c50ee6d453ad5a650c43a73aa03a311.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ea8c62af19011d7171da2e6719c031c4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48fe5d9cbe4f83926f5c21912df67a2e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1f22fec5a381ae8aca93d876e54c79de.png)
②任意一个非负实数都可写成一个数的平方的形式.即:如果a≥0,则
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/14db6be2d25013aa7d212e9bab0929ae.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/26af9120fdb4ec6a51ac5749aabc1015.png)
例:①用配方法求代数式
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09e449af388d5092ab975d3d738a5b48.png)
②已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/94440d3e4c073f94f2b266ff99d50e74.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f88df0e33729786eabb92177cb45ede6.png)
①解:由题意得:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/35c94cad4a74a8908238a0387474b4e9.png)
∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fe514f68aa8d8bc076f3c027133fd323.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/707ea658f3a9359f5740d5aab48f7948.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c0dc9632bf7a57e4a5903fa74d61adb2.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/04c005b3286bf45ce90a7c47157de3dd.png)
∴当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/707ea658f3a9359f5740d5aab48f7948.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09e449af388d5092ab975d3d738a5b48.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d13ce3ebd1112220c639562739f1f9d1.png)
②证明:∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/94440d3e4c073f94f2b266ff99d50e74.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5995e8774decd9d4fe698c109a4acdc0.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f88df0e33729786eabb92177cb45ede6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2a9b68d7a85015a2a76b1e41e5c593c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/759e6d90078d6d79e68c55e39e118d78.png)
请解答下列问题:某园艺公司准备围建一个矩形花圃,其中一边靠墙(墙足够长),另外三边用篱笆围成(如图所示).设垂直于墙的一边长为x米.
![](https://img.xkw.com/dksih/QBM/2022/10/12/3085898821697536/3086626708406272/STEM/5637c5a1db474a71a154c4077d63e4fe.png?resizew=147)
(1)若所用的篱笆长为36米,那么:
①当花圃的面积为144平方米时,垂直于墙的一边的长为多少米?
②设花圃的面积为S米
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/921ef5abce73648e3834140df9a72aa8.png)
(2)若要围成面积为200平方米的花圃,需要用的篱笆最少是多少米?
您最近一年使用:0次