如图,
是平面四边形
的一条对角线,已知
,且
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/26/f482ed50-9b3d-466e-b5be-9c9671bb8e13.png?resizew=185)
(1)求证:
为等腰直角三角形;
(2)若
,
,求四边形
面积的最大值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4355c3b7f9a75c91aae33d869f0350b3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dcc535649e4f8c842a63d724bfd8cc9.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/26/f482ed50-9b3d-466e-b5be-9c9671bb8e13.png?resizew=185)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5bb961bd7db3adb76af2d4cedb611bd7.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef0402dd5ae3db10281f9f1e11738bcb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/037b342a682cbd4241855a243da3c016.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
更新时间:2020-02-15 22:45:51
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相似题推荐
解答题
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【推荐1】在
中,
的对边分别为
,
,
的面积为
.
(Ⅰ)求
的值;
(Ⅱ)求
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4f9caf437daaf34d6075df028e9999a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ff40647acc39fdcdcd5f3e19b29b103f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0aae4da8b8d5cd29946e897cc1553c9b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/84e4123975f257306440158659634c4a.png)
(Ⅰ)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/071a7e733d466949ac935b4b8ee8d183.png)
(Ⅱ)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bffdb513e6877c6c58cc60136c954259.png)
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【推荐2】设
的内角
的对边分别为
,且![](https://staticzujuan.xkw.com/quesimg/Upload/formula/32065efa78afa4762ef3c092979e6eaa.png)
(1)求角
的大小;
(2)若
,
,求
的面积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0faed94a64b2dcfc6801b4fca0f16675.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24e0c10fb103930eabd5fa18e8f9bb06.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76f0649064a085fb74c997fb507a9b6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/32065efa78afa4762ef3c092979e6eaa.png)
(1)求角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aa4c355f11471a38f5583a434a1ddeb3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68abf671ba1bc7cbf2704f1dfde481d2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0faed94a64b2dcfc6801b4fca0f16675.png)
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【推荐1】如图,某班级学生用皮尺和测角仪(测角仪的高度为1.7m)测量重庆瞰胜楼的高度,测角仪底部A和瞰胜楼楼底O在同一水平线上,从测角仪顶点C处测得楼顶M的仰角,
(点E在线段MO上).他沿线段AO向楼前进100m到达B点,此时从测角仪顶点D处测得楼顶M的仰角
,楼尖MN的视角
(N是楼尖底部,在线段MO上).
(2)若测角仪底在线段AO上的F处时,测角仪顶G测得楼尖MN的视角最大,求此时测角仪底到楼底的距离FO.
参考数据:
,
,
,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6cb7249184f583db0d938ec9794f7b56.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/04351d9bd6729649ac2a5208b9b7aec8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/056c8e4d974739fe1525b9d62a7b697c.png)
(2)若测角仪底在线段AO上的F处时,测角仪顶G测得楼尖MN的视角最大,求此时测角仪底到楼底的距离FO.
参考数据:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b1f5e98fc62232b6523f9fcfd68ec9e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/79d257bec4e4e849114c9dc206b6016b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08f33acd67f70af387e70c6253a1a0fc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a3e98dbf4bd297abeadb9bc2057023cf.png)
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【推荐2】如图,平面四边形ABCD中,
,
,
.
的内角A,B,C的对边分别为a,b,c,且满足
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/19/9bb9192c-3302-4255-ac90-743b474ae953.png?resizew=120)
(1)求四边形ABCD的外接圆半径R;
(2)求
内切圆半径r的取值范围.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ecf7679c8b4b1e442ce4286d4b0e9c32.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/55c24a968c73e960698a572ab01e3698.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f7dbf31dfd36aa456a63bafea8bc1985.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e72269fac0f6af36b496a953f6ef37b3.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/19/9bb9192c-3302-4255-ac90-743b474ae953.png?resizew=120)
(1)求四边形ABCD的外接圆半径R;
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
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【推荐1】设
,
是两个不共线的非零向量.
(1)若
,
,
三向量的起点相同,终点在一直线上,求实数
的值;
(2)若|
|=|
|=1,且
与
夹角为60°,求向量
与向量
夹角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a2f4b1178f68bd147d1a2a6acd04435.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c94075193c11fe43f2396cff5a485054.png)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a2f4b1178f68bd147d1a2a6acd04435.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68948b2f70759841724c2399bd1521ec.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/de4e95ea682ccc52f3390cd00d3fd0ca.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36a1b09c653185842513e24ebba60bb3.png)
(2)若|
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a2f4b1178f68bd147d1a2a6acd04435.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c94075193c11fe43f2396cff5a485054.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a2f4b1178f68bd147d1a2a6acd04435.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c94075193c11fe43f2396cff5a485054.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b83c5803cc8c05849028a57c4bd4ee72.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1bca35e52b8430246a1cf96e9e617cce.png)
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解答题-证明题
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【推荐2】(1)已知
,
,点
在线段
的延长线上,且
,求点
的坐标;
(2)若
是夹角为
的两个单位向量,求:(i)
的值;(ii)函数
的最小值;
(3)请在以下三个结论中任选一个用向量方法 证明.
①余弦定理;②平行四边形的对角线的平方和等于其四边长的平方和;③三角形的三条中线交于一点.
注:如果选择多个结论分别解答,按第一个解答计分.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/98b2cc0d2f6d3eee9a33db83e0c0830d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4dd8a31b5335186eb1bea5c80cddcfd9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e490ca1cc66be5a2f1677d243fe093db.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8e8b95a61af300412fc65f846089028.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be6a6301878fed2a01413020b27310a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/58054eff6c328eb401995a81c6e91a54.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7d65f84320b2cea4c64a8254bbceb250.png)
(3)请在以下三个结论中任选一个用
①余弦定理;②平行四边形的对角线的平方和等于其四边长的平方和;③三角形的三条中线交于一点.
注:如果选择多个结论分别解答,按第一个解答计分.
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【推荐3】已知
.
(1)求
与
的夹角;
(2)求
;
(3)若
,求实数k的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/52394ef45205d22ad6ab2b07ff367382.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/64c5562bd4d1b54424330cb6329cd79d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b45ba716f03748c19b7ce2f99af536ab.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/93af88a7628c71d642d3a6df067c15f5.png)
(3)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f3fc739cda498045685c0fb4bf25bd49.png)
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