![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/627cdca2bc6c5efc65150e922e26d1dc.png)
(1)求角A的大小;
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9a2dd89c37b60b4596ac30e339aa0000.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
更新时间:2022-05-17 20:00:15
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【推荐1】在平面四边形ABCD中,AD=BD=1,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/29/4f3a9df4-5378-4707-ac7b-b5499891adc2.png?resizew=144)
(1)求四边形ABCD面积的最大值;
(2)求对角线AC长的取值范围.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/32dd60bbaeb26c5ba07faa4415cc4655.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/29/4f3a9df4-5378-4707-ac7b-b5499891adc2.png?resizew=144)
(1)求四边形ABCD面积的最大值;
(2)求对角线AC长的取值范围.
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【推荐2】在
中,角
,
,
所对的边分别为
,
,
,已知
,且
的外接圆的半径为
.
(1)证明:
;
(2)若
,求
的面积.
![](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/01e83f77cd56f9781dd84b0fd388f106.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/35361e76a7c85d1886728c8d0200b234.png)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57cdc66e435de8c70232bc5f5ff4b703.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ffe7a93172d308a58200e3c722fe1072.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
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【推荐1】十七世纪法国数学家、被誉为业余数学家之王的皮埃尔·德·费马提出的一个著名的几何问题:“已知一个三角形,求作一点,使其与这个三角形的三个顶点的距离之和最小.”它的答案是:“当三角形的三个角均小于
时,所求的点为三角形的正等角中心,即该点与三角形的三个顶点的连线两两成角
;当三角形有一内角大于或等于
时,所求点为三角形最大内角的顶点.”在费马问题中所求的点称为费马点. 试用以上知识解决下面问题:已知
的内角
所对的边分别为
,且![](https://staticzujuan.xkw.com/quesimg/Upload/formula/89eb1f8d4ef5f7299d746fff1b8d7222.png)
(1)求
;
(2)若
,设点
为
的费马点,求
;
(3)设点
为
的费马点,
,求实数
的最小值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a6c0927afc571a7c966c98192040979e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a6c0927afc571a7c966c98192040979e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a6c0927afc571a7c966c98192040979e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.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/89eb1f8d4ef5f7299d746fff1b8d7222.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/44ac38c5cc951497a4a37778b191bcce.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3b8f8a1e38db0e55b9b1934569b24e74.png)
(3)设点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b01862dfc85d45102a1343c36cb6dfe5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36a1b09c653185842513e24ebba60bb3.png)
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【推荐2】宜昌卷桥河湿地公园是一幅美丽的田园湿地画卷,它将自然山体、阳光草坪、亲水草滩、芒草湿地、溪谷密林等有机融合,设计的十分精致优美.为了迎接2023年的春天,公园里开辟了一块等腰直角三角形
农田种植七彩油菜,其斜边
米.为了方便游客观光,欲在
上选择一点
,修建两条观赏小径
,点
分别在边![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1cfd2cfa70c66adb6440ed5f627b12ea.png)
上,且小径
与边
的夹角都是
.区域
和区域
种植粉色油菜,区域
种植黄色油菜.
(1)随着春天到来,油菜均已开花,为了游客深度体验观赏,准备在种植黄色油菜区域内修建小径
,当点
在何处时,三条小径(
)的长度之和最小?
(2)种植粉色油菜的成本是100元/平方米,求种植粉色油菜的最少费用.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6067415c47436e3d8782aabdc01e4847.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2352fd3ab9597b8256a41675bc0404bd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7789a500686c7a73770404ead6af0590.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1cfd2cfa70c66adb6440ed5f627b12ea.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2352fd3ab9597b8256a41675bc0404bd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d88591679796c52024d11c4de641bdb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e4c6194fc8da1c11fd875e6597e914f2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8860aa439bd9d3ab7e0df4bd1f2a28b4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/69a0982460d2fdf7f28aabe7f8ae01e6.png)
(1)随着春天到来,油菜均已开花,为了游客深度体验观赏,准备在种植黄色油菜区域内修建小径
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aa7ae07d6c95b0c2e5723a864ce08c1a.png)
(2)种植粉色油菜的成本是100元/平方米,求种植粉色油菜的最少费用.
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【推荐1】已知直线l过点
,与x轴正半轴交于点A、与y轴正半轴交于点B.
(1)求
面积最小时直线l的方程(其中O为坐标原点);
(2)求
的最小值及取得最小值时l的直线方程.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d00d5d8cc31aaca7fc2eafb99eac7629.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3fe95f656b98b53f71a9d72bf0c9a4b9.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/abe1edfa25bb35a13621066bca829fb3.png)
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【推荐2】已知某气垫船的最大船速是
海里/时,其中
,船每小时使用的燃料费用和船速的平方成正比.当船速为30海里/时时,船每小时的燃料费用为600元,而其余费用(不论船速为多少)都是每小时864元.船从甲地行驶到乙地,甲乙两地相距100海里.
(1)试把船每小时使用的燃料费用
(单位:元)表示成船速
(单位:海里/时)的函数;
(2)试把船从甲地到乙地所需的总费用
(单位:元)表示成船速
(单位:海里/时)的函数;
(3)当船速为多少时,船从甲地到乙地所需的总费用最少?
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1a5fa62e2ce679fd94f5fbbcdfdaff4a.png)
(1)试把船每小时使用的燃料费用
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bc13a607ac0c7f76d252d7cb1bb040fd.png)
(2)试把船从甲地到乙地所需的总费用
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d053b14c8588eee2acbbe44fc37a6886.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bc13a607ac0c7f76d252d7cb1bb040fd.png)
(3)当船速为多少时,船从甲地到乙地所需的总费用最少?
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