通过前面的学习,我们知道了
和
这三个特殊角的三角函数值,下面让我们一起尝试探究
角的正切值吧!
(1)方法一:如图1,在
中,
,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/56d3c9ce32b721995f355eea411340e3.png)
方法二:如图2,在等腰三角形
中,
,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/74a7f2699f32d766e61f58a385aba1e7.png)
(2)根据
角的正切值的探究过程,请尝试求
角的正切值,直接写出答案.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a4e2da6f9254b607129f771a6b8be2ba.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be6a6301878fed2a01413020b27310a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76c12e76fbd84eeec721386bd3b04cc4.png)
(1)方法一:如图1,在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd967903ed5a6f640a5b801ec8be0070.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7e3262fc038bbec5e7c8cc47df08bef7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/56d3c9ce32b721995f355eea411340e3.png)
步骤 | 操作方法 | 具体过程 |
步骤一 | 在含![]() ![]() | 延长![]() ![]() ![]() ![]() ![]() |
步骤二 | 找到含有![]() ![]() | 在![]() ![]() ![]() ![]() |
步骤三 | 计算![]() | 则![]() |
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ffe8a84ca3a13f82aff1a022edc66065.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/43dad1f58af0e8cb85dd1bfa7df597b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/74a7f2699f32d766e61f58a385aba1e7.png)
步骤 | 操作方法 | 具体过程 |
步骤一 | 在顶角为![]() ![]() | 过点E作![]() ![]() 可以找到 ![]() ![]() |
步骤二 | 找到含有![]() ![]() | (请自己写出具体过程) |
步骤三 | 计算![]() | 则![]() |
(2)根据
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76c12e76fbd84eeec721386bd3b04cc4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cbe53cbaa36cecf802efc9e81e9937ac.png)
更新时间:2024-01-01 14:41:56
|
相似题推荐
解答题-证明题
|
适中
(0.65)
【推荐1】我们知道:在一个三角形中,相等的边所对的角相等.那么,不相等的边所对的角之间的大小关系怎样呢?如图,通过观察发现:在
中,
大于
,
边所对的
大于
边所对的
.为了证明这一发现,解决思路是构造全等三角形将
转化为一个三角形的外角,利用三角形的外角大于不相邻的内角使问题得以证明.
请根据以上思路,完成以下作图与填空:
中,
.求证:
.
(1)尺规作图:作
的平分线
,交
于点
,在
上截取
,连接
.(保留作图痕迹)
(2)证明:∵
平分
,
∴__________.
在
和
中,
,
∴
,
∴
__________,
∵
__________,
∴
.
![](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/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/194741f4d2ae7ee44cafca780361446a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/febc9a89d0d1c97b88c0f4acd32b4e67.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/194741f4d2ae7ee44cafca780361446a.png)
请根据以上思路,完成以下作图与填空:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/abcb980da8e86b4cfd322616dc84fc6e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce6f337c00a6d4bf1e7580d8888db3d6.png)
(1)尺规作图:作
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7cbce11aa19b8bd2bf6ee5a834e005de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20a541b81584a032f571159ea152c85a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.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/934a9508c176f44bf58f88715bd98f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
(2)证明:∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20a541b81584a032f571159ea152c85a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7cbce11aa19b8bd2bf6ee5a834e005de.png)
∴__________.
在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6cb3e973f4e9361e1d23a0ab56006d12.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a4a514e2e338c6fa31c9938624a4a71.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8c41d262534d2ad03bdba9339b557e90.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d08f5ed79c64045ba9df4d6844a9e932.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/459459559720ab5e154a80723c47cc30.png)
∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3a472cacfa350ab52dd5d4eceb4712bd.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce6f337c00a6d4bf1e7580d8888db3d6.png)
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【推荐2】如图①所示为五角星图案,图②、图③叫做蜕变的五角星,试回答以下问题.
(1)在图①中,
__________;
(2)对于图②或图③,还能得到同样的结论吗?若能,请在图②或图③中任选其一证明你的发现;若不能,试说明理由.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/10/15/f0da0ce8-f44a-406c-83eb-fbb6b9d78449.png?resizew=387)
(1)在图①中,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a5866ae0703a7c111e65f9f8990e354.png)
(2)对于图②或图③,还能得到同样的结论吗?若能,请在图②或图③中任选其一证明你的发现;若不能,试说明理由.
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【推荐1】已知,△ABC是等边三角形,D、E、F分别是AB、BC、AC上一点,且∠DEF=60°.
(1)如图1,若∠1=50°,求∠2;
(2)如图2,连接DF,若∠1=∠3,求证:DF∥BC.
(1)如图1,若∠1=50°,求∠2;
(2)如图2,连接DF,若∠1=∠3,求证:DF∥BC.
![](https://img.xkw.com/dksih/QBM/2020/9/2/2541343440732160/2545874164875264/STEM/35f800da96824653abe8d61259856858.png?resizew=313)
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【推荐2】(1)如图1,AD平分∠BAC,AE⊥BC,∠B=30°,C=70°,求∠DAE的度数;
(2)如图2,AD平分∠BAC,点F在AD的延长线上,FE⊥BC,∠B=28°,∠C=68°,求∠DFE的度数;
(3)如图3,AD平分∠BAC,EA平分∠BEC,∠C﹣∠B=38°,求∠DAE的度数.
(2)如图2,AD平分∠BAC,点F在AD的延长线上,FE⊥BC,∠B=28°,∠C=68°,求∠DFE的度数;
(3)如图3,AD平分∠BAC,EA平分∠BEC,∠C﹣∠B=38°,求∠DAE的度数.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/18/0b09ebee-30cb-48f5-8ab6-a3b395037e1c.png?resizew=492)
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【推荐3】【概念认识】
如图①,在
中,若
,则BD、BE叫做
的“三分线”.其中,BD是“邻AB三分线”、BE是“邻BC三分线”.
在
中,
,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/998329f9cdb86f5d60d7d5d70fc3781e.png)
(1)如图②,BD是“邻AB三分线”,则
的度数是________°;
(2)如图③,BD、CD分别是
和
的邻BC三分线,则
的度数是________°;
【延伸推广】
(3)在
中,若
,BD、CD分别是
和
的邻BC三分线,则
的度数是________°(用含m的代数式表示);
【延伸拓展】
在
中,BD、CD分别是
和
的邻BC三分线.
,
,则
的度数是________°(用含m的代数式表示);
(5)将直线MN绕点D旋转,与线段AC交于点N,与射线CB交于点M,请直接写出
与
的数量关系________°(用含m的代数式表示).
如图①,在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d39b8d91afc34e4a9b0fdbb6bafb9087.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/907010738647677858b8d8300d920341.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d39b8d91afc34e4a9b0fdbb6bafb9087.png)
在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ba53ecdf811c43d45bdf9b277be3dc97.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/998329f9cdb86f5d60d7d5d70fc3781e.png)
(1)如图②,BD是“邻AB三分线”,则
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a72dfbf0138a611174c36ce077e0c47.png)
(2)如图③,BD、CD分别是
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d39b8d91afc34e4a9b0fdbb6bafb9087.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8fabb884dc5f9609de491245463bbe9a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0c543c3ddc3723fde6bbfca3ea3b921b.png)
【延伸推广】
(3)在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/878e48357ec37956f4d8fb656e7bed8a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d39b8d91afc34e4a9b0fdbb6bafb9087.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8fabb884dc5f9609de491245463bbe9a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0c543c3ddc3723fde6bbfca3ea3b921b.png)
【延伸拓展】
在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d39b8d91afc34e4a9b0fdbb6bafb9087.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8fabb884dc5f9609de491245463bbe9a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/31307b00524e461b0ad8dfbcdf24bacf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/878e48357ec37956f4d8fb656e7bed8a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48ccccde1e0a4d6d69853c297b1307b5.png)
(5)将直线MN绕点D旋转,与线段AC交于点N,与射线CB交于点M,请直接写出
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/474e47a4679cace57ffd2b870f5b13a2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e265894011c2b93ce5a5fa9fab2b9982.png)
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解答题-证明题
|
适中
(0.65)
【推荐1】如图,在
中,
,
,将
绕点
按逆时针方向旋转100°得到
,连接
,
交于点
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/22/c0005f0a-f0c4-4a43-a05c-892ead2bcbca.png?resizew=176)
(1)求证:
;
(2)求
的度数;
(3)求证:四边形
是平行四边形.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/047dc9795efa99b6fb9fdf9778085dab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed10ad623f3a05ecdc27b3f3e0169669.png)
![](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/a25c28359f8d8da9eaf4672a6cf8ae4f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/22/c0005f0a-f0c4-4a43-a05c-892ead2bcbca.png?resizew=176)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/421291381be28da4bd16560fd383b4a9.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/246a86f34603eaf2e6a948681b831b0d.png)
(3)求证:四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/369eb8ad56da7dc1cdb7c43762be4bee.png)
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【推荐2】如图,
,
,
平分
,
的垂直平分线分别交
、
于F、G,求证:
.
![](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/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8fabb884dc5f9609de491245463bbe9a.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/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6953f3ee4ae67a70266712b559e2d0d1.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/7/748d06d9-4185-455e-974e-78215ec764f5.png?resizew=168)
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解答题-问答题
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【推荐1】如图,
的面积为12,
,
.点M在边AB上(点M与点A不重合),连结DM,作点A关于直线DM的对称点
,连结
、
.
![](https://img.xkw.com/dksih/QBM/2022/5/31/2991227185659904/2992254938161152/STEM/7f74854a-64e7-44a1-81f5-ea9f8eba5bc3.png?resizew=224)
(1)点D到直线AB的距离是______.
(2)设点
到直线BC的距离为d,求d的最小值.
(3)当点
落在
的边上时,求AM的长.
(4)当直线
与
的一边垂直时,直接写出AM的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5138a9f70d5e8b0580e30fef6eb7baef.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/305a88d4e0249bd16d48eda01331d2d4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d0d5a2cd05e4476fc72271e8fdb59a9a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7c314398e26ffc7164b82946eeb4273.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e42198b8e646ccfbbec323fd364c4d90.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6a21897349d3d7c94419692106887153.png)
![](https://img.xkw.com/dksih/QBM/2022/5/31/2991227185659904/2992254938161152/STEM/7f74854a-64e7-44a1-81f5-ea9f8eba5bc3.png?resizew=224)
(1)点D到直线AB的距离是______.
(2)设点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7c314398e26ffc7164b82946eeb4273.png)
(3)当点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7c314398e26ffc7164b82946eeb4273.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5138a9f70d5e8b0580e30fef6eb7baef.png)
(4)当直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e42198b8e646ccfbbec323fd364c4d90.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5138a9f70d5e8b0580e30fef6eb7baef.png)
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【推荐2】如图,
为的
直径,
是弧
的中点,
与
,
分别交于点
,
.
(1)若
,求证:四边形
是菱形;
(2)若
的半径
,且
,求
的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.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/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/683c590673eece14fea3319c4fd5eb55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/11/10/58e54970-81c0-4932-bda4-b9b508d486db.png?resizew=148)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85fb581e6a89ae40731b8619fff1e173.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f4b3773da38cc94fdc6951f6e5c20ddd.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b72d83915b41102495fcff91dbdbb0b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ee32e148b131c5d451163280a0317ded.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
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