1 . 已知动点P到直线
的距离是P到点
距离的2倍,点P的轨迹记为C.
(1)证明:存在点
,使得
为定值.
(2)过点F且斜率
的直线l与C交于A,B两点,M,N为x轴上的两个动点,且
,
,若
,求k.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f23d29646155e27b172ecdf263e2d702.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b2ba2238d6afe0187534155dd9ac48c6.png)
(1)证明:存在点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f8e55590555905eb4f57889bbd16e39a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/17ed50b7ddc736c4a2fad6a58135e03f.png)
(2)过点F且斜率
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2f0d68648b10fce54dfc19c5ee60086d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d99e9ab44437147165c319705daad0fe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/339f691f01e9fb0e30570d5daad31002.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c0dc4ea85e09c94960e4f1c20657e117.png)
您最近一年使用:0次
2023-01-09更新
|
412次组卷
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4卷引用:青海省西宁市大通回族土族自治县2023届高三一模数学(理)试题
名校
2 . 秦九韶,字道古,鲁郡(今河南范县)人.中国古代数学家.他是一位非常聪明的人,处处留心,好学不倦.时人说他“性极机巧,星象、音律、算术,以至营造等事,无不精究”,秦九韶还创用了“三斜求积术”等,给出了已知三角形三边求三角形面积公式,与古希腊数学家海伦(Heron,公元50年前后)公式完全一致.学习数学,就要“知其然,知其所以然.”请你用所学的解三角形知识,推导证明海伦-秦九韶公式:
,其中
,
,
,
分别为
中角
,
,
所对的边.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e35b7eae154f81e66d2191ef1142da5e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0f2d50ca5cc415bf6721faf2221d626.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)
![](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)
您最近一年使用:0次