如图所示,某住宅小区一侧有一块三角形空地
,其中
,
,
.物业管理部门拟在中间开挖一个三角形人工湖
,其中
,
都在边
上(
,
均不与
,
重合,
在
,
之间),且
.
![](https://img.xkw.com/dksih/QBM/2022/7/7/3017420236382208/3019543356727296/STEM/5c2d3a6999014acfb9871871796c997c.png?resizew=251)
(1)若
在距离
点
处,求点
,
之间的距离;
(2)设
,
(i)求出
的面积
关于
的表达式;
(ii)为节省投入资金,三角形人工湖
的面积要尽可能小,试确定
的值,使
的面积最小,并求出这个最小面积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dc83f34b5a3c1dc09d990ce4bdc8e078.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a29ac2834e2f2f1c32149fe31f107134.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9fd446f72000300a54fb9e1e28325093.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20ccc37b189fa2cbc269ca0b233dac37.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e17dc84ba2e871aeb3a3fd2a2b5f1a8.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/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.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/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a9b0eb72986587ffecf87c22a224bcd2.png)
![](https://img.xkw.com/dksih/QBM/2022/7/7/3017420236382208/3019543356727296/STEM/5c2d3a6999014acfb9871871796c997c.png?resizew=251)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a26016c9a610be4da74086a37c3327d8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0fb35158a52a23a6e57ff890cef8c7cf.png)
(i)求出
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/25dd698d57d1cf239eb8752aecaaa4f4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf231f8f86fb922df4ca0c87f044cec3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c24095e409b025db711f14be783a406c.png)
(ii)为节省投入资金,三角形人工湖
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e17dc84ba2e871aeb3a3fd2a2b5f1a8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c24095e409b025db711f14be783a406c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/25dd698d57d1cf239eb8752aecaaa4f4.png)
更新时间:2022-07-10 13:39:35
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解题方法
【推荐1】在三角形ABC中,角A,B,C所对的边分别是a,b,c,若2bcosB=acosC+ccosA
(1)求角B的大小;
(2)若线段BC上存在一点D,使得AD=2,且AC
,CD
1,求S△ABC.
(1)求角B的大小;
(2)若线段BC上存在一点D,使得AD=2,且AC
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a88baedfc1deeee9e85138abddfdd000.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ef9a0e4373f1154bc4534b4ae59b872.png)
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【推荐2】在△ABC中,
.
(1)求
的大小;
(2)若
, .求
,并计算
的面积;
从①
, ②
这两个条件中任选一个,补充在上面问题中并作答.
注:如果选择多个条件分别解答,按第一个解答计分.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a90b6031f23002f0bc7a2f40eb37ac7f.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ae7888d643678ea18f83f3237732052.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
从①
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ab1c19b66cda3fb899f06d9a25e973c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3578b63c5903089595bf324c809a997c.png)
注:如果选择多个条件分别解答,按第一个解答计分.
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【推荐1】已知函数
.
(1)求函数
的单调递减区间;
(2)在锐角
中,角
、
、
所对边分别为
,
,
,其中
,
,若
,求
的面积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/64b352ecbf9b011ae2febf81fb1f2093.png)
(1)求函数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4fe7d5809da02c15a43a0e9a898b9086.png)
(2)在锐角
![](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/f12c618da29d3e2e341a8c2dc974a6fd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3320a13248a3a1208ff6ee85c9d26f36.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42a30cdeccc312028502c30ca324d62e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
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解答题-证明题
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解题方法
【推荐2】已知
分别为
三个内角A,B,C的对边,满足:
.
(1)证明:
;
(2)若
,且
为锐角三角形,求
的面积S的取值范围.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d90d7f054e8f0346479e1999622f11cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a65efadf9b71b05903ba0f4f40b8595b.png)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c7b9446d7b31f0d6e044cf99deeb20aa.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3320a13248a3a1208ff6ee85c9d26f36.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
您最近一年使用:0次
解答题-问答题
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适中
(0.65)
解题方法
【推荐1】已知函数
.
(1)求函数
的最小值和最小正周期;
(2)已知
内角
、
、
的对边分别为
、
、
,满足
且
,
,求
、
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a6035416bb2abed78636119b5179803e.png)
(1)求函数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09f86f37ec8e15846bd731ab4fcdbacd.png)
(2)已知
![](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/bf621ba581a7d271d40e2b505b7159dd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dcb5bac75f36bb1dc5c8190d4dbe681d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b22e4c9f482aee8735f3c38bdbe70402.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c94bb12cee76221e13f9ef955b0aab1.png)
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【推荐2】(1)四点共圆是平面几何中一种重要的位置关系:
如图,
,
,
,
四点共圆,
为外接圆直径,
,
,
,求
与
的长度;
①(托勒密定理)任意凸四边形,两组对边的乘积之和不小于两条对角线的乘积,当且仅当该四边形的四个顶点共圆时等号成立.
②(婆罗摩笈多面积定理)若给定凸四边形的四条边长,当且仅当该四边形的四个顶点共圆时,四边形的面积最大.
根据上述材料,解决以下问题:
,
,
,
,求线段
长度的最大值;
(ii)见图2,若
,
,
,求四边形
面积取得最大值时角
的大小,并求出此时四边形
的面积.
如图,
![](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/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a651eb577dbada1f29590e558d6f9fa2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0ab5c45a72849d2cae1d65b282b5bd19.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d2c15801fee2405573677484f5dcfa4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
①(托勒密定理)任意凸四边形,两组对边的乘积之和不小于两条对角线的乘积,当且仅当该四边形的四个顶点共圆时等号成立.
②(婆罗摩笈多面积定理)若给定凸四边形的四条边长,当且仅当该四边形的四个顶点共圆时,四边形的面积最大.
根据上述材料,解决以下问题:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21ea52361458ce2e49ed0fe99d8e6c02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aa7aeb2a8d1437eeb4482c3b6ad9f315.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/422f54faa21cdabc65b912b0e76eb68e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/212bfbd5575772ca36d6fc3e7b246e49.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
(ii)见图2,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcd0ced286a0fbc7e4862f8147264277.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/07160f14b3b453bebb64cb2bf96dc85a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/89c41757ae282475fb29ec1e8e02045d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
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