1 . 已知
的三边长
,三内角为
.求证:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f7f5573b30734d65648f61c0a94c98de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/38335830b93ac4d99c28a8e209eecb3f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7b102b36cba4c1868afcd7a591a796da.png)
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2 . 在
中,角
所对的边分别为
,且
.
(1)判断
的形状,并加以证明;
(2)当
时,求
周长的最大值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/38335830b93ac4d99c28a8e209eecb3f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f7f5573b30734d65648f61c0a94c98de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/748d27f8027ed7b499ba7db2f2e49081.png)
(1)判断
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4580cc037c0c760c728cdbb74a8154c6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
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解题方法
3 . 如图1,在
中,
,
,点D,E分别在边AB,AC上,
,连接DC,点M,P,N分别为DE,DC,BC的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/8/d3f9bf69-239d-4a2f-afa6-ab13bae095de.png?resizew=392)
(1)观察猜想:图1中,线段PM与PN的数量关系是________,位置关系是________;
(2)探究证明:把
绕点A逆时针方向旋转到图2的位置,连接MN,BD,CE,判断
的形状,并说明理由;
(3)拓展延伸:把
绕点A在平面内自由旋转,若
,
,请直接写出
面积的最大值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd967903ed5a6f640a5b801ec8be0070.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8f89deb952f57f4b3fa4887b098b7b91.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/047dc9795efa99b6fb9fdf9778085dab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2d212c1709b8e72a055cf1b5381ef64.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/8/d3f9bf69-239d-4a2f-afa6-ab13bae095de.png?resizew=392)
(1)观察猜想:图1中,线段PM与PN的数量关系是________,位置关系是________;
(2)探究证明:把
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a25c28359f8d8da9eaf4672a6cf8ae4f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1ed4c4e8edbd179f3fc38a6653f18c1.png)
(3)拓展延伸:把
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a25c28359f8d8da9eaf4672a6cf8ae4f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc11331a7b2d2619b40ee6d34c3bd620.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc34db5860990e51ba31edc8cdd077c2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1ed4c4e8edbd179f3fc38a6653f18c1.png)
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名校
解题方法
4 . 在
中,
、
、
分别是角
、
、
的对边,已知向量
,向量
,向量
,若
,
,求证:
为等边三角形.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c94bb12cee76221e13f9ef955b0aab1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/071a7e733d466949ac935b4b8ee8d183.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/a294138169a338323a41707cbc858530.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e9664bd0e6a93288d6160239f151a80d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/604ff270a575d14620cd5e815add1d56.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2758285d3c1d8c16784edbc5f572fc26.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/493b351ad48bab60c205f91c0a4449fb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
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5 . 已知
中,三内角
、
、
的度数成等差数列,边
、
、
依次成等比数列.求证:
是等边三角形.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.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/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c94bb12cee76221e13f9ef955b0aab1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/071a7e733d466949ac935b4b8ee8d183.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
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2020高三·全国·专题练习
6 . 在
中,设
分别是内角
所对的边,且直线
与
平行,求证:
是直角三角形.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76f0649064a085fb74c997fb507a9b6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24e0c10fb103930eabd5fa18e8f9bb06.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a6e009787e8e3f08cd13c2931addb2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9a250e1e2f07dee96dc07d40dec6e22b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
您最近一年使用:0次
解题方法
7 . 在
中,
,
分别在线段
上,且
,
.(
)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/12/f27a86c7-4bfd-4ee6-a3d1-d971ac70d2d7.png?resizew=133)
(1)若
,求证:
;
(2)设
,且
,求
的最大值.
![](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/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cede22a31bcdb9a94a7448cc49997369.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5adaead91b4b6febfcdd6f995d81e550.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0291bbe0ccccc1cd14b5a20eb70c82f0.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/12/f27a86c7-4bfd-4ee6-a3d1-d971ac70d2d7.png?resizew=133)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7788830ed1cb3b9c5988f70f43595f2e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f913298f0fae9f55377a8deab9f099dd.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ed20b1e8b2b850779a23d5fa2744384.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/79ff9df563f934ee442444b8e5d5cd35.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
您最近一年使用:0次
8 . 如图,正方形
的边长为
,
,
分别为边
和
上的点,且
的周长为2.
![](https://img.xkw.com/dksih/QBM/2021/1/6/2630196112523264/2633078219218944/STEM/88df7da9d2d24d72b0261d861cc58b01.png?resizew=174)
(1)求证:
;
(2)求
面积的最小值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdaa19de263700a15fcf213d64a8cd57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/31f6c430883f98d3c6502fdb9cb0a64c.png)
![](https://img.xkw.com/dksih/QBM/2021/1/6/2630196112523264/2633078219218944/STEM/88df7da9d2d24d72b0261d861cc58b01.png?resizew=174)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8e75b8c50824fbbdb7328b47d9f2b04f.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d53407b42c690396db22f8278be30623.png)
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解题方法
9 . 在
中,角
,
,
所对的边分别为
,
,
.已知
.
(1)证明:
是直角三角形.
(2)若
为
的中点,且
,求
面积的最大值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.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/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c94bb12cee76221e13f9ef955b0aab1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/071a7e733d466949ac935b4b8ee8d183.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3b47b0347adf59923545d4a84acbe50b.png)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
(2)若
![](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/267ace52b64e1e7dfc5211e033255b7d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
您最近一年使用:0次
2020-12-03更新
|
468次组卷
|
5卷引用:三湘名校教育联盟五市十校教研教改共同体2020-2021学年高三上学期11月大联考数学试题
10 . 如图,在山脚
测得山顶
的仰角为
,从
处沿斜坡向上走
米到达
处,在
处测得山顶
的仰角为
,且斜坡
的倾斜角
.求证:山高
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b5858ee1ce52b251816757257a11c29.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c270b86732d6b7ec6325b55ee354c8bc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61f81ce17a3d13f8f0d8aeb47b27b153.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/3/29802e8c-6b0b-427f-ab51-67cf88c62b4a.png?resizew=240)
您最近一年使用:0次