如图,等边
中,点
是
延长线上一点,点
在
上,连接
,
.
,求证:
平分
;
(2)如图2,点
为线段
上一点,连接
交
于点
,若点
为
的中点,求证:
;
(3)如图3,点
为线段
上一动点,作
关于
的对称点
,连接
,
,交
于点
,点
在
的延长线上运动,始终满足
,连接
,
交
于点
,当
取得最大值时,此时
,
,求整个运动过程中
的最小值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/64d5fcee996a47e9cc3cfd4ba108f21e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7cd1bc0388e7fad3e849ca39c67f5034.png)
(2)如图2,点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/274cf35acb4a1748d15c39d15a9bea7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/274cf35acb4a1748d15c39d15a9bea7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd8e8b8dc232a88228f377b7782db172.png)
(3)如图3,点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f8e55590555905eb4f57889bbd16e39a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cad0a19415e796564f30906f2e7dbf76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/98120e6349f8f31317ef8a5c10992ead.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf3834d7ec7531f3c3c0ce9b286f7a49.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd8e8b8dc232a88228f377b7782db172.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c47cf6148d7d0b9a95a72734c34ad85a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/274cf35acb4a1748d15c39d15a9bea7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c47cf6148d7d0b9a95a72734c34ad85a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e86f844639b5856311dd85215f472958.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c6a2e40c699f8f32b6f35242802bff11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0e57a13c665af88f326c9890072bf73.png)
22-23八年级上·重庆江北·期中 查看更多[2]
更新时间:2023-01-23 00:00:39
|
相似题推荐
解答题-证明题
|
困难
(0.15)
解题方法
【推荐1】已知四边形ABCD是正方形,点P在直线BC上,点G在直线AD上(P,G不与正方形顶点重合,且在CD的同侧),PD=PG,DF⊥PG于点H,交直线AB于点F,将线段PG绕点P逆时针旋转90°得到线段PE,连结EF.
(1)如图1,当点P与点G分别在线段BC与线段AD上时.
①求证:DF=PG;
②若AB=3,PC=1,求四边形PEFD 的面积;
(2)如图2,当点P与点G分别在线段BC与线段AD的延长线上时,请猜想四边形PEFD 是怎样的特殊四边形,并证明你的猜想.
![](https://img.xkw.com/dksih/QBM/2020/5/8/2458233223839744/2458373654274048/STEM/d3cd69574a4f451b85935bc9c1245c06.png?resizew=125)
(1)如图1,当点P与点G分别在线段BC与线段AD上时.
①求证:DF=PG;
②若AB=3,PC=1,求四边形PEFD 的面积;
(2)如图2,当点P与点G分别在线段BC与线段AD的延长线上时,请猜想四边形PEFD 是怎样的特殊四边形,并证明你的猜想.
![](https://img.xkw.com/dksih/QBM/2020/5/8/2458233223839744/2458373654274048/STEM/d3cd69574a4f451b85935bc9c1245c06.png?resizew=125)
![](https://img.xkw.com/dksih/QBM/2020/5/8/2458233223839744/2458373654274048/STEM/405d87b84d8a46cfaf00c37f561de8d9.png?resizew=125)
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【推荐2】如图1,
和
都是等腰三角形,
,
,
与
分别交于点
和
交于点G,连接
.
(1)若
,求
的度数;
(2)如图2,连接
求证:
垂直平分
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a25c28359f8d8da9eaf4672a6cf8ae4f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1acd11641d792896bc235d173b2cd66d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c6af731695bce37849870c23a7768e77.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fe182142c22def2860792c7c5b6b99f8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57f93189c1761325a34527b260fbd5d7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8518c9bd112f86afb26eec99b01934d8.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/10/f4ad8b6c-7823-422c-8b26-d0d69f08dad7.png?resizew=146)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/931136cb6b341e8ad0fedbd144561e22.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/721c75fcd58d3d54260aad0f82e09e37.png)
(2)如图2,连接
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f78f02b08ada74b3b0df609a886c517e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/826c728050e3378921442ace20269ef6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/10/8aaf4c1e-3224-40bc-97eb-d3c05a9b2a6c.png?resizew=148)
您最近一年使用:0次
解答题-证明题
|
困难
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名校
【推荐3】综合与实践
综合与实践课上,老师让同学们以“正方形的折叠”为主题开展数学活动.
(1)㩧作猜想
操作一:对折正方形纸片
、使
与
重合,得到折痕
,把纸片展平;
操作二:继续沿
折叠,使点D落在正方形内部点G处,把纸片展平,连接
、
;
根据以上操作:在图2中写出一个与
相等的角______.
(2)探究证明
①如图3,延长
与边
交于点
,连接
,则
与
的大小关系是______;线段
、
、
之间的数量关系是______;
②判断点
在
上的位置、并说明理由.
(3)拓展延伸
如图4,若正方形的边长为
,直接写出点
到线段
的距离.
综合与实践课上,老师让同学们以“正方形的折叠”为主题开展数学活动.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/10/6/3ab51e22-f6a2-403b-8879-9ba00862b826.png?resizew=387)
(1)㩧作猜想
操作一:对折正方形纸片
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
操作二:继续沿
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/31e55e398e8520d8a36fb5a625a085b8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/abf80148409afb32ced0b4f59f1ba709.png)
根据以上操作:在图2中写出一个与
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b7c76218f2fea5d94763e21f27285e4e.png)
(2)探究证明
①如图3,延长
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/31e55e398e8520d8a36fb5a625a085b8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73465a1f9aa03481295bf6bd3c6903ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a6655e2fa64a32cd12fe0279afd65d73.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6ae55a0c2394db34861f116b0a6d3b0e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/527ba12c15182827768fdb327ca29869.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a16f5621716bfef7a056a3f2712feb4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bcdae78f4d3b8d8213ac3ac9a9567eb5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
②判断点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73465a1f9aa03481295bf6bd3c6903ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
(3)拓展延伸
如图4,若正方形的边长为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/095ab4a92bf822e175d370e6d0c8a730.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
您最近一年使用:0次
解答题-证明题
|
困难
(0.15)
【推荐1】已知P是△ABC内任意一点(如图).
(1)求证:
(a+b+c)<PA+PB+PC<a+b+c;
(2)若△ABC为正三角形,且边长为1,求证:PA+PB+PC<2.
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f89eef3148f2d4d09379767b4af69132.png)
(2)若△ABC为正三角形,且边长为1,求证:PA+PB+PC<2.
![](https://img.xkw.com/dksih/QBM/2011/12/1/1573289726099456/null/STEM/4501b6b26b06490c96a9461ecef7d042.png?resizew=116)
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解答题-问答题
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困难
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【推荐2】如图,边长为8的等边三角形
中,D,E分别是
边的中点,点P从B点沿着折线
运动,连接
绕点A逆时针旋转60°到点Q.
(1)如图1,当点P在
上运动时,求
的度数;
(2)如图2,连接
,设P点的运动速度为每秒1个单位长度,运动时间为t,请求出
的面积S关于t的函数关系式;并指出t的取值范围;
(3)当
是直角三角形时,直接写出此时
的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/787ac5e13622afab5e9f8603afe42356.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/893bd35964001f6481611f8929bcf8a1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/937ce16f676e06ed7612a1061da93701.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f5a127d42dfb12478798365dadcc092a.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/8/9/4c2da14e-f675-4976-874d-7bf89c2323e4.png?resizew=670)
(1)如图1,当点P在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b3182db896bc2462331796e2a6108363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e875682c8dfcd4981243a41579703c6.png)
(2)如图2,连接
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/45330d7fcd8829b408ec2ee57b641f8c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8d7ad020b11f04f6b9b6f5ce766ad11c.png)
(3)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e5547ed68c4897c2a5e4403ff17dde6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80672dda9430cb42b3136bcb1b67bbad.png)
您最近一年使用:0次
【推荐1】在平面直角坐标系中,点
为原点,点
的坐标为
.如图1,正方形
的顶点
在
轴的负半轴上,点
在第二象限.现将正方形
绕点
顺时针旋转角
得到正方形
.
(1)如图2,若
,
,求直线
的函数表达式.
(2)若
为锐角
,当
取得最小值时,求正方形
的面积.
(3)当正方形
的顶点
落在
轴上时,直线
与直线
相交于点
,
的其中两边之比能否为
?若能,求点
的坐标;若不能,试说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f79821f22f666a97f26d3350512f5da.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ab158dd9e96abcae0f115f54fa66c5b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ab158dd9e96abcae0f115f54fa66c5b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b670c6d27ce68f17ac12c4efa1933db1.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/8/9/e0e7933a-2628-41eb-bf67-07860eeb7b64.png?resizew=418)
(1)如图2,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6c96cb3ac8290e09c55d4eb336a8608.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/539017d54be655fef3e26d2292a58e0a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/18fafc016dedb418df05cdbb12305f4c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b670c6d27ce68f17ac12c4efa1933db1.png)
(3)当正方形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b670c6d27ce68f17ac12c4efa1933db1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d053b14c8588eee2acbbe44fc37a6886.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c63e36329f5e0979f5ee776ac5d06327.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/22a70b91e48c6c0435789cc656a19465.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6d76e86c1dcc191aa8d51b3a528a454d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
您最近一年使用:0次
解答题-证明题
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困难
(0.15)
【推荐2】(1)问题:如图
在
中,
,
,
为
边上一点(不与点
,
重合),连接
,过点
作
,并满足
,连接
.则线段
和线段
的数量关系是_______,位置关系是_______.
(2)探索:如图
,当
点为
边上一点(不与点
,
重合),
与
均为等腰直角三角形,
,
,
.试探索线段
,
,
之间满足的等量关系,并证明你的结论;
(3)拓展:如图
,在四边形
中,
,若
,
,请直接写出线段
的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40cba83244c4f6b87c88859d89f252a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cfa8cee7d2463f6f7d352e8b65f47cf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c06154cae3bf7a8ce5a1e97a7380875.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/047dc9795efa99b6fb9fdf9778085dab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.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/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8b1472e121da0ae5550329cfda5f0a2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e30e50e094cd2849e38859b36aad0b0c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
(2)探索:如图
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.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/cfa8cee7d2463f6f7d352e8b65f47cf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/507e12d9f005670d07bb30c15ee8596c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/26813466e2ee49a493881a4384fc8748.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/047dc9795efa99b6fb9fdf9778085dab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2d212c1709b8e72a055cf1b5381ef64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/abb3c143721938422cde08e0690fac88.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4fa12efe16e6c4ef0ec08a078ecbb5a2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4a7a6901af6bf907d2baf1b42a0a704d.png)
(3)拓展:如图
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ca7d1107389675d32b56ec097464c14.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2894a6ff5b198184fffcaa1d03a33227.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/32f01c4faacedfe56f5127d6c0cc63cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/037b342a682cbd4241855a243da3c016.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://img.xkw.com/dksih/QBM/2020/3/2/2410826431488000/2410932842840064/STEM/65c4ca19874848d8b4a695eab3834dca.png?resizew=450)
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