名校
1 . 我国汉代数学家赵爽在证明勾股定理时,创制了一幅“勾股圆方图”,后人称之为“赵爽弦图”.如图,大正方形
由4个全等的直角三角形和一个小正方形
组成,
,
,
.
.
(2)若直角三角形
的面积为
,
,求小正方形
的边长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/611f100dcfa7803db6eb233e2e7f2dab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c884a45b56bc34d79273b067c1520b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/44b9fb616a125f49b4b68057c62aa80c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1c95370ad095bf8caf76fc457e218db4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3133ef62aad6bdd6637140620f068fad.png)
(2)若直角三角形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c09afc70f448545336304333d5b5658b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd2142368b10234525598c5c32dad846.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63957fe9482fe2fb7aa6a1cda2ac0c01.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/611f100dcfa7803db6eb233e2e7f2dab.png)
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2024-02-26更新
|
131次组卷
|
3卷引用:河北省石家庄市平山县外国语中学2023-2024学年八年级下学期月考数学试题
2 . 聪聪和妍妍都用长为4l厘米的铁丝折矩形.聪聪折成的是正方形,其面积记为
平方厘米;妍妍折成的是长、宽不相等的长方形,其一边长为a厘米,其面积记为
平方厘米.
(1)请用含l和a的式子分别表示
,
;
(2)当
、
时,请比较
、
的大小;
(3)请先猜想
、
的大小,再用求差法证明你的猜想.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e097c8d4c948de063796bd19f85b3a9a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e0bd63f55069a3bc870915010b39225.png)
(1)请用含l和a的式子分别表示
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e097c8d4c948de063796bd19f85b3a9a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e0bd63f55069a3bc870915010b39225.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f8bc6928ed8e05cbc566fd502fb17fab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aa4c355f11471a38f5583a434a1ddeb3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e097c8d4c948de063796bd19f85b3a9a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e0bd63f55069a3bc870915010b39225.png)
(3)请先猜想
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e097c8d4c948de063796bd19f85b3a9a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e0bd63f55069a3bc870915010b39225.png)
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3 . “字母表示数”被后人称为从“算术”到“代数”的一次飞跃,用字母表示数可以从特殊到一般的表达数学规律.请观察下列关于正整数的平方拆分的等式:
第1个等式:
;第2个等式:
;
第3个等式:
;第4个等式:
;
(1)请用此方法拆分
.
(2)请你用上面的方法归纳一般结论,用含n(n为正整数)的等式表示,并借助运算证明这个结论是正确的.
(3)嘉嘉尝试借助图形的面积验证(2)中的结论.思路是将边长为n的正方形(如图)进行适当分割,请你帮助他完成画图,并在图中标出相应线段的长度.
第1个等式:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1ea3f882a328e1f0c095c391ea6088a2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c02321a6c5ee65fb06a974cc824fa8e2.png)
第3个等式:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/efff091efd6bfb1d91660e4e40207d0d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/71252523ea94008679783b6dc3e67ae2.png)
(1)请用此方法拆分
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdd9db35163a2307b50d94a4a045abc0.png)
(2)请你用上面的方法归纳一般结论,用含n(n为正整数)的等式表示,并借助运算证明这个结论是正确的.
(3)嘉嘉尝试借助图形的面积验证(2)中的结论.思路是将边长为n的正方形(如图)进行适当分割,请你帮助他完成画图,并在图中标出相应线段的长度.
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4 . 数学活动课上,同学们根据学习“二次根式”及“乘法公式”积累的经验,通过“由特殊到一般”的方法,探究“当
,
时,
与
的大小关系”.
下面是探究过程.
①具体运算,发现规律:
当
,
时,
特例1:若
,则
;
特例2:若
,则
;
特例3:若
,则
;
②观察、归纳,得出猜想:
当
,
时,
.
③证明猜想:
当
,
时,
,
,
当且仅当
时,
.
请你利用发现的规律,解答以下问题.
(1)当
时,
的最小值为 .
(2)当
时,
的最小值为 .
(3)当
时,
的最大值为 .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/94440d3e4c073f94f2b266ff99d50e74.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/67ca5fd57c2c2fcc3c7a574fdd1467d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/78d7009d4cbe7157d63ce50444443716.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20d6fc9b90f370fbb27552876b650f8f.png)
下面是探究过程.
①具体运算,发现规律:
当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/94440d3e4c073f94f2b266ff99d50e74.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/67ca5fd57c2c2fcc3c7a574fdd1467d9.png)
特例1:若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4a7dbc702617c765a573961953cc0901.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7c2ab3fb94127e9387c4768625dd4735.png)
特例2:若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8792eaab0b6464e5d07436c64aa751a2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a92d69a89d4c3a7539e9c2d4fa22df8.png)
特例3:若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/289295fad0d1c11fc74470e8bb0c6be0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42c1f4b0f20cbdf818307c775295e9d9.png)
②观察、归纳,得出猜想:
当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/94440d3e4c073f94f2b266ff99d50e74.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/67ca5fd57c2c2fcc3c7a574fdd1467d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/655937ddffcee20a01e0a51d08667a1b.png)
③证明猜想:
当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/94440d3e4c073f94f2b266ff99d50e74.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/67ca5fd57c2c2fcc3c7a574fdd1467d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5fb00f1be7f539241416eca219d5b2cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0c013070499776fca6c98e715ec048c1.png)
当且仅当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1f22fec5a381ae8aca93d876e54c79de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8f8baa567e0f1f335254b41fb84a3076.png)
请你利用发现的规律,解答以下问题.
(1)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08115d6d9f876dea921a4d32260ff1fb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/13f40c24c64bbb0645fcf585f4e66872.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e541ea2f855f981c96207070683d388.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0fdf9746b211aa64dd8fcd0ed51c95eb.png)
(3)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e541ea2f855f981c96207070683d388.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c9b32409a74c71d11061fdd71d7c17f5.png)
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5 . 观察下列等式:
①
;
②
;
③
;
④
这些等式反映了某种规律.
(1)请你写出第6个等式_____;
(2)试用含
(
,且
为正整数)的式子,表示你发现的规律,并证明你发现规律的正确性.
①
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8d0b9da574079677a11cf49bda7f9532.png)
②
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2869587cdbf7093d1aef256acd717ff.png)
③
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/22569c4f899112b97a835ed03174d25d.png)
④
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a073852199fc3d27defe28e6b216a98a.png)
(1)请你写出第6个等式_____;
(2)试用含
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e167b43045b3297248e334c41c621b8f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
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6 . 定义:任意两个数á,b,按规则
扩充得到一个新数c,称所得的新数c为“求实数”.
(1)若
,
,求出a,,b的“求实数”c;
(2)如果![](https://staticzujuan.xkw.com/quesimg/Upload/formula/abc4b9930d569a48586cd54d607eb797.png)
求a, b的“求实数”c,并证明:无论 m取何值时“求实数”c总是非正数;
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/26b29f890747733d0fa2feaf792df390.png)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e65397f11ea8af736f38debadf420c4a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6f06408895febc126c2ae409e807349c.png)
(2)如果
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/abc4b9930d569a48586cd54d607eb797.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2db9a58e185e4fd9c4f86efb24480f1.png)
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7 . 发现:两个连续偶数的平方差一定是偶数,且这个偶数等于这两个偶数之间的奇数的四倍,例如:
,则
可以表示为______的四倍;
验证:若两个连续偶数的平方差刚好是9的四倍,求这两个偶数;
探究:n表示两个连续偶数中较小的数,用含n的等式表示“发现”中的结论,并证明.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/880158b725ac616f6aa450ae633929c1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2f03f8cefc8350d84ed1563c1ef355cc.png)
验证:若两个连续偶数的平方差刚好是9的四倍,求这两个偶数;
探究:n表示两个连续偶数中较小的数,用含n的等式表示“发现”中的结论,并证明.
您最近一年使用:0次
2023-09-23更新
|
74次组卷
|
2卷引用:河北省石家庄市第二十八中学2022-2023学年九年级下学期开学考试数学试题
8 . 图1是一个长为
、宽为
的长方形,沿图中虚线用剪刀均分成四块小长方形,然后按图2的形状拼成正方形
.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/3/12/2d754d4e-1ecd-4865-9f34-5bdf528dfd23.png?resizew=252)
(1)观察图2填空:正方形
的边长为______,阴影部分的小正方形的边长为______;
(2)观察图2,试猜想式子
,
,
之间的等量关系,并证明你的结论;
(3)根据(2)中的等量关系,解决如下问题:已知
,
,求
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fad491e5b5e14c49ef8b7004ebcfcef9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2d51f9147b8265c0276c1f2c2659197.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/3/12/2d754d4e-1ecd-4865-9f34-5bdf528dfd23.png?resizew=252)
(1)观察图2填空:正方形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
(2)观察图2,试猜想式子
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b792c557283debf4d450681258a59adf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c8b5acd59e0c5f5de7e070a75e04b651.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1019d4ad2e3fb4a7abb66e0e9e55b556.png)
(3)根据(2)中的等量关系,解决如下问题:已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20ddd4c4f98bcd2c9fc5909851f07a65.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/12982a37030cf5af1770b8bb50645676.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20d6fc9b90f370fbb27552876b650f8f.png)
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9 . 已知整式
的值为
,
的值为
.
(1)【发现】当
时,
,
__________,
__________
(填“
”“=”或“<”);
当
时,
__________,
,
__________Q.
(2)【猜想与验证】无论
为何值,
__________
始终成立,并证明该猜想的结论.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2de5862b4d8a00f7ed2312076916334.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/042d0202ad76c7dfb20653d8b3261aeb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
(1)【发现】当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3b4d795709b0abcf47bceec2250f2f9b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acfaedeb3a7c1e032f3e7974471284ea.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f7b2a80b41ffdb9089018e2b9654a858.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/392cdb9d30684cce244bef94b8d861b9.png)
当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e65397f11ea8af736f38debadf420c4a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e989c65b1aaa8812e0e8bb6983c2bd0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bb24c3698a3c072f3c1845f9ad96b36b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
(2)【猜想与验证】无论
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
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10 . 设
表示一个两位数,其中
是十位上的数字(
),例如,当
时,
表示的两位数是45.观察以下等式:
①当
时,
;
②当
时,
;
③当
时,
;
……
根据以上规律,解决下列问题
(1)写出第六个等式:______
(2)写出你猜想的第
个等式(用含
的式子表示),并证明:
(3)运用:若
与
的差为2525.求
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/048620d06732edebf16c6fb6cf8064c3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bbcd9199d40a04d12c2edf052020636e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fac3649308b528fd56545ba102dc42d5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/048620d06732edebf16c6fb6cf8064c3.png)
①当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c87b351f16728b0023fd63678f8103c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9261ce7c2e5e38e511b7a69fb0933d0b.png)
②当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cc2d3df37e73a8abea815f37dbb3fff5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7998a832096ba76a28c5a49a8cbdee11.png)
③当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be604061cf1591f7069472269d4c9719.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be60f754221dc15ceb23d44f5b66a99a.png)
……
根据以上规律,解决下列问题
(1)写出第六个等式:______
(2)写出你猜想的第
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
(3)运用:若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/93a56027ad9cbf25fafa4572b2ac70c0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dcacafc923ed47e9abc99d59833b421e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
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2023-05-11更新
|
120次组卷
|
2卷引用:2023年河北省秦皇岛市海港区中考一模数学试题