1 . 观察如下四个图形,并根据图中规律回答相关问题.
在图1中,D是
中
边的二等分点,图2中D、E是
边的三等分点,图3中D、E、F是
边的四等分点……图4中D、E、F、G是
边的n等分点,过各等分点的线段分别与底边
平行.设
的面积为
,过各等分点与底边平行的线段分三角形各部分的面积分别为:
,
、
……
,由两个相似三角形的面积比等于相似比的平方可得:
①当D是
边的二等分点:
;
②当D、E是
边的三等分点:
;
③当D、E、F是
边的四等分点:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6539e5bbd1bec2786816a6d6021e8e75.png)
……
按照以上规律,解决下列问题:
(1)写出第④个等式:
______.
(2)请你猜想出
的结果(用含n的式子表示),并验证你的猜想.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/11/4/572bc5e0-3896-446f-8081-387c8a511025.png?resizew=473)
在图1中,D是
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf231f8f86fb922df4ca0c87f044cec3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e097c8d4c948de063796bd19f85b3a9a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e0bd63f55069a3bc870915010b39225.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6899bf9cadae2ccdb14cbc87d4f280ee.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
①当D是
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/65c3dbf6e7719a048c4bf5f3d0d0b4f1.png)
②当D、E是
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6595ef0992d8882577ea42ed5909af2f.png)
③当D、E、F是
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6539e5bbd1bec2786816a6d6021e8e75.png)
……
按照以上规律,解决下列问题:
(1)写出第④个等式:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/614306cc3f34bdee4d5d885b79667645.png)
(2)请你猜想出
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
您最近一年使用:0次
2 . 如图,
是边长为1的等边三角形,顶点O在平面直角坐标系的原点处,
在x轴上,点A在第一象限.以点O为位似中心将
作位似变换.第一次变换后得到
,
与
的相似比为
;第二次变换后得到
,
与
的相似比为
;……按此规律,第n次变换后得到
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/11/71ecde6d-81a0-4b01-8062-a3e8cada72fd.png?resizew=205)
(1)填空:点
的坐标为__________,
的坐标为__________,
的坐标为__________,
的坐标为__________.
(2)直接写出点
和点
的坐标.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3fe95f656b98b53f71a9d72bf0c9a4b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b90e0f35eda1a729fed485f83da5ea9d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3fe95f656b98b53f71a9d72bf0c9a4b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/beb99c20237aca8ff2ba640c28fbc5b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3fe95f656b98b53f71a9d72bf0c9a4b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/beb99c20237aca8ff2ba640c28fbc5b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ee625166d9a321e5856770276ff253fc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ef3e5e30a5d97b80edfa260b43c3e02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/beb99c20237aca8ff2ba640c28fbc5b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ef3e5e30a5d97b80edfa260b43c3e02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ee625166d9a321e5856770276ff253fc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c75e563a1219cc5b71503a618ecfb7d8.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/11/71ecde6d-81a0-4b01-8062-a3e8cada72fd.png?resizew=205)
(1)填空:点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a18722354086c42e62334983fc50eb6a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cd3b9e816b14051f785aa5aae72b8eed.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/97c01fdc7bc471af0b264a04aef0823e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/43a71fc9c0068109dad1382354570665.png)
(2)直接写出点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d3cfeacc29e6a61c5b3b4e439c0a91df.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/249b92e30f3808f5287db70a9eec6a53.png)
您最近一年使用:0次
3 . 某同学用一等边三角形木板制作一些相似的直角三角形.如图,其方法是:过C点作
于
,再过
作
于
,再过
作
于
,…,若
的边长为a,则
,
,
,依此规律,则
的长为( )
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/13/d88cbd57-1fff-46a8-b4ae-aaf9d1252e6a.png?resizew=181)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d83a4b5dcca35dc02215eb9e1b03636b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6795cae2df43a722e1355e9562d93c09.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6795cae2df43a722e1355e9562d93c09.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/53b0de09b447d9fc8b231e31c9dddde1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c296e45b84cf67a98939aa7334e7d478.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c296e45b84cf67a98939aa7334e7d478.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/044d04a40fa4e57d6763028af27afc60.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/de8ce8c07e34224e2d25130ed27c9a98.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5698d34b69032233a9adeb761efdce17.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bc42b07132a7765f3a4617683ff5c137.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/964b58eed54c02bd571c6bed3173464a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b62f60056eb1dccd166d9f8736c9aad7.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/13/d88cbd57-1fff-46a8-b4ae-aaf9d1252e6a.png?resizew=181)
A.![]() | B.![]() | C.![]() | D.![]() |
您最近一年使用:0次
4 . 如图,菱形
中,
,
坐标为
,再以
为对称中心作菱形
,再以
为对称中心作菱形
,按此规律继续作下去,得到菱形
,则
的坐标为_______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/59f35d4ede5b91b03d09a99262de2693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ceee2f6c71fd337a7d70bcf1ab201741.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/97c01fdc7bc471af0b264a04aef0823e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fab8a0cc6504aa4c3a38006f5394b4c2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/97c01fdc7bc471af0b264a04aef0823e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2ffbf8da591ea12fb59a5dad95dccd38.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/43a71fc9c0068109dad1382354570665.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/753690831380320812b972727dd77c86.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/39f3859be33e902e3dbd03727539363d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d3cfeacc29e6a61c5b3b4e439c0a91df.png)
![](https://img.xkw.com/dksih/QBM/2021/5/10/2718140753674240/2793157994717184/STEM/d72eb6f4-9cf4-46af-9849-5245c964bd17.png)
您最近一年使用:0次