如图,在等腰
中,
,
为
的中点,
,垂足为
,过点
作
交
的延长线于点
,连接
.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/4/7/e0636616-839f-4e1d-b7fe-3d72c182ad5f.png?resizew=200)
(1)求证:
.
(2)连接
,试判断
的形状,并说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd967903ed5a6f640a5b801ec8be0070.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed10df4140819d5451773a45de66201b.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/32c38dfd14dde969702dff97ef2270f9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fe446a0456e9168028baee032d8d7d23.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4cae70b8a9d2d2e96dea62c00ced04b9.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/4/7/e0636616-839f-4e1d-b7fe-3d72c182ad5f.png?resizew=200)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e521605c1066839c8cf71f0941b36d6d.png)
(2)连接
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54fb6e81fee5674c3e26a65e58cc506d.png)
更新时间:2024-04-09 14:38:30
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相似题推荐
解答题-问答题
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适中
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【推荐1】如图所示,一条公路修到湖边时,需要拐弯绕湖而过,如果第一次拐的角
,第二次拐的角
,第三次拐的角为
,若
与
平行,则
等于多少度?说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/284a563413dc0532138fb2a64db8cc2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8ceeb6ac7f248397e846f5b61fac6c2f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/194741f4d2ae7ee44cafca780361446a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b66a5b7813e902306477f91f9f4084cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/167d31eb8432b5c0364316e5048c23dd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/194741f4d2ae7ee44cafca780361446a.png)
![](https://img.xkw.com/dksih/QBM/2019/8/15/2269165179805696/2269204499849216/STEM/b169fc100f074d2a975ad819123a8024.png?resizew=220)
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【推荐2】如图,在
中,
,点
是
的中点,将
沿
折叠后得到
,过点
作
交
的延长线于点
.求证:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2f8f88798ec42a58dccd212586382b23.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7e3262fc038bbec5e7c8cc47df08bef7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6b1bd1adfe4cc6566218f19970c2fd3b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7ac451db3443cabb204f96c31fd4a02e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c771a4feb150ad9cff8d70431c97eb17.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1da81b8a99d67f8e9ab147a32cd57886.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/193ea44749f1c64c8723e84a57d15cb9.png)
![](https://img.xkw.com/dksih/QBM/2020/5/2/2453883062550528/2454967064420352/STEM/2a3608198c9849b2906e9f3e7403d4c8.png?resizew=263)
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【推荐2】如图,在
与
中,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/16f3d198e76391779fa3badc848c8ac8.png)
,
,
,连接
且
,连接
.
(1)求证:
;
(2)若
,求
的长度.
(3)
和
有何位置关系?请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d631f45bc652539853f236952afa5bbf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/16f3d198e76391779fa3badc848c8ac8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a78f1b109b3c6d2390f0afb8e2513d8f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b10134e7a46e6f6f7cb9d5e2371727d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/347c8f892b0544ce1a5a0c7a8ab4bd64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7d97dc3b752832906de41447bb58a341.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7059ac1fdadf0bc6474d78c03ac7e121.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/10/20/4daac7b4-bcaa-4462-a2db-bd293a9177dd.png?resizew=162)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc8c5a0011c9af0c81b06e0b9b6dee3c.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0cc3dcc4325297dac77a92c0682a6cad.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
(3)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
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解答题-证明题
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【推荐1】综合与探究
![](https://img.xkw.com/dksih/QBM/editorImg/2023/11/13/83e01e56-6b13-43cb-999a-098bbdc1d5ae.png?resizew=610)
数学兴趣小组活动中,张老师提出了如下问题:如图1,在
中,
,求
边上的中线
的取值范围.
小明在组内经过合作交流,得到了如下的解决方法(如图2).
①延长
到点
,使得
;
②连接
,通过三角形全等把
转化在
中;
③利用三角形的三边关系可得
的取值范围为
,从而得到
的取值范围.
方法总结:上述方法我们称为“倍长中线法”.“倍长中线法”多用于构造全等三角形和证明各边之间的关系.
(1)根据小明组内的做法,能得到
的依据是_______,
边上的中线
的取值范围是_______.
(2)灵活运用:如图3,在
中,
是
的中点,点
在
边上,点
在
边上,若
,求证:
.
(3)拓展延伸:以
的边
为边向外作
和
,
是
的中点,连接
.当
时,请直接写出
的长.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/11/13/83e01e56-6b13-43cb-999a-098bbdc1d5ae.png?resizew=610)
数学兴趣小组活动中,张老师提出了如下问题:如图1,在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2664e0c44eaa5487cd8b99772f68a80a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
小明在组内经过合作交流,得到了如下的解决方法(如图2).
①延长
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bbcb7dd920a799716b5e5febbe4954d6.png)
②连接
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e69d2b798744645af88a4fa411344a83.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5690cfcbb8a0b6da61bf64f1026be443.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20a5e0a51c9e14fb246b0ba0b231c1e3.png)
③利用三角形的三边关系可得
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d50703c46b6153945d718b198f03b4b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9daa99b481401c3dd6581a07dd6d17ad.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
方法总结:上述方法我们称为“倍长中线法”.“倍长中线法”多用于构造全等三角形和证明各边之间的关系.
(1)根据小明组内的做法,能得到
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e8454c9cb0bc6f224d265a1736a26dda.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
(2)灵活运用:如图3,在
![](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/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e47f2874795e9df280e3e0bec171358e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e17c1c2b2b0a45b267e3a33d169737e.png)
(3)拓展延伸:以
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7dec2ca6438c82b43f746057d8129885.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e742966e3711cfa53dce04022acf4bcc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3467fbd936eee89194c1afcc74eda1dc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/037ac3db1e176432acd190b891eb9d73.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aa3fb0e69e5f9f6eba8e35d629d118b1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e3432d20e661779ddcefda76afcc2ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
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解答题-作图题
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适中
(0.65)
【推荐2】如图,已知△ABC.
①请用尺规作图法作出AC边的垂直平分线,交AB于D点;(保留作图痕迹,不要求写作法)
②在(1)的条件下,连接CD,若AB=15,BC=8,求△BCD的周长.
①请用尺规作图法作出AC边的垂直平分线,交AB于D点;(保留作图痕迹,不要求写作法)
②在(1)的条件下,连接CD,若AB=15,BC=8,求△BCD的周长.
![](https://img.xkw.com/dksih/QBM/2019/6/25/2233246270480384/2233415409614849/STEM/7e0112801f274d5fb1c62122fb807d7c.png?resizew=144)
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解答题-问答题
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适中
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【推荐1】【问题呈现】
在
中,
,
,点
是斜边
上的一点,连接
,试说明
、
、
之间的数量关系,并说明理由.
【解决策略】小敏同学思考后是这样做的;如图1将
绕点
逆时针旋转
,得到
,连接
,经过推理使问题得到解决,请回答:
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/23/da370d21-bfdb-42a4-8c64-6f41c85a4efc.png?resizew=201)
(1)
的形状是 ,
的形状是 ;
(2)直接写出
、
、
之间的数量关系是 ;
【方法感悟】若条件中出现等线段共端点,可以考虑旋转某个三角形,把分散的条件或结论集中到一个三角形中.
(3)如图2,在四边形
中,
,
,
,若
,
,求
的长;
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/23/4209162c-0711-4c01-976a-aba10540cc22.png?resizew=169)
(4)如图3,在四边形
中,
,
,若
,
.求
,
两点之间的最大距离.
在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2f8f88798ec42a58dccd212586382b23.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed10df4140819d5451773a45de66201b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d89ba4036a5d18ec4abed44d7fd8e89.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/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
【解决策略】小敏同学思考后是这样做的;如图1将
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a4a514e2e338c6fa31c9938624a4a71.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c02b54dc6b3e1bb6544f47d4c8743fcf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fd0c32d9f3badb7e51233dd39a39fbb3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/23/da370d21-bfdb-42a4-8c64-6f41c85a4efc.png?resizew=201)
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/abe4bdc5d9e833b23a1b916c06fc1a35.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3a0acc93490a6a784eb62201d93dd93d.png)
(2)直接写出
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
【方法感悟】若条件中出现等线段共端点,可以考虑旋转某个三角形,把分散的条件或结论集中到一个三角形中.
(3)如图2,在四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bb18ca22c75425698cd5f0da2671e1c0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/386c7de62e8f9a8161ebaefe6b4ec35e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/67b686b84b7a2b8e2326dbb88af5e855.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0ff29971ccc633d89832ffa9bd54afa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b59ab6bf6111dda4a3d428454768b77.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e673ef2d48215ca84a48377f17d6df00.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9abaeba15f3abdd877bc701af52c5cd9.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/23/4209162c-0711-4c01-976a-aba10540cc22.png?resizew=169)
(4)如图3,在四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f945a69cf7e8213e50622125cde652f5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e735a28578ba191da6d4f3b0f8e8729.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7788830ed1cb3b9c5988f70f43595f2e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/833cfda415649b832cc136caed392753.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/23/9fb712ea-5dd8-4e95-b97e-4d40f25aeea6.png?resizew=114)
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名校
【推荐2】(1)【问题发现】
中,
,
,点D为
的中点,以
为一边作正方形
,点E与点A重合,易知
,则线段
与
的数量关系是________;
(2)【拓展研究】
在(1)的条件下,将正方形
绕点B旋转至如图2所示的位置,连接
,
,
.请猜想线段
和
的数量关系,并证明你的结论;
(3)【结论运用】
在(1)(2)的条件下,若
的面积为8时,当正方形
旋转到C、E、F三点共线时,请直接写出线段
的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd967903ed5a6f640a5b801ec8be0070.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/047dc9795efa99b6fb9fdf9778085dab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c06154cae3bf7a8ce5a1e97a7380875.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f84f169e50dc59d4f7a8e1e36f5c847.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/66c82f63629f47be223bff9e628da0f8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
(2)【拓展研究】
在(1)的条件下,将正方形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f84f169e50dc59d4f7a8e1e36f5c847.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
(3)【结论运用】
在(1)(2)的条件下,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f84f169e50dc59d4f7a8e1e36f5c847.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
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