题目
题型:不详难度:来源:
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024091957-90117.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024091957-96627.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024091957-98342.png)
(1)求动点P的轨迹C的方程;(2)直线
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024091958-35858.png)
答案
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024091958-33933.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024091958-20797.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024091958-37358.png)
解析
试题分析:(1)显然动点
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024091959-33111.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024091959-62719.png)
故设直线FD的方程为
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024091959-65079.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024091959-10897.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092000-92051.png)
把直线
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092000-84243.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092000-76636.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092000-63897.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092000-56517.png)
可得关于
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092000-63897.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092000-63897.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024091959-10897.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092000-84243.png)
线方程联立,利用韦达定理求出
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092000-76823.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092001-39777.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092000-76823.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092000-63897.png)
解方程即可,需根据
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024091959-10897.png)
试题解析:(1)依题意,动点P的轨迹C是以
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024091957-90117.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024091957-96627.png)
所以动点P的轨迹C的方程为
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024091958-33933.png)
(2)解法一:因为
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024091957-90117.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024091959-65079.png)
联立方程组
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092001-59786.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092001-36864.png)
解得
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024091959-10897.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092001-83123.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092002-89277.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092002-70355.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092002-38003.png)
又由
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092002-78474.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092003-89647.png)
设
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092003-76886.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092003-82507.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092003-11129.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092003-38584.png)
所以
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092004-76338.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092004-91246.png)
因为FABD为平行四边形,所以
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092004-35212.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092005-74680.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092002-38003.png)
解得
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024091958-20797.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024091958-37358.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092005-27105.png)
(2)解法二:因为
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024091957-90117.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024091959-65079.png)
联立方程组
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092001-59786.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092001-36864.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092001-83123.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092002-89277.png)
故点
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092005-59145.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092005-85478.png)
1)当
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092005-59145.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092005-54463.png)
联立方程组
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092006-82257.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092006-48197.png)
根据韦达定理有
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092006-19542.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092006-83154.png)
又因为四边形是平行四边形,所以
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092001-39777.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092006-40248.png)
代入①有
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092007-93786.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092007-59791.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092007-94146.png)
整理得
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024091958-20797.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092007-50304.png)
2)当
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092005-85478.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024092007-36614.png)
核心考点
试题【已知点,直线,动点P到点F的距离与到直线的距离相等.(1)求动点P的轨迹C的方程;(2)直线与曲线C交于A,B两点,若曲线C上存在点D使得四边形FABD为平行四】;主要考察你对抛物线的定义与方程等知识点的理解。[详细]
举一反三
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024091952-11359.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024091952-62350.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024091952-92259.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024091953-76174.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024091953-64605.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024091953-65070.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024091953-50655.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024091953-11208.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024091943-47462.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024091944-58931.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024091944-88432.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024091944-67411.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024091944-99821.png)
A.![]() | B.![]() | C.4 | D.![]() |
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024091935-87465.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024091932-61338.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024091926-13586.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191024/20191024091926-96304.png)
最新试题
- 1下列说法正确的是( )A.任何原子都是由质子、中子和电子构成的B.因为原子中质子带正电,中子不带电,故整个原子显正电C
- 2下列句子的横线上应填入的关联词语,最恰当的一项是[ ]①花和人都会遇到各种各样的不幸,
- 3现有下列器材:电压表V1(量程3V,内阻约几千欧)电压表V2(量程6V,内阻约几十千欧)定值电阻R1(3.0k)滑动变阻
- 4已知数列{an},an>0,且3(a21+a22+…+a2n)=(2n+1)(a1+a2+…+an).(1)求a1,a2
- 5下列各句中有语病的一句是( )A.以1994年创办的“焦点访谈”“新闻纵横”为代表,广播电视的舆论监督不仅成为十一届
- 6(26分)读图我国两地相关的相关材料,回答下列问题。云量是以一天内云遮蔽天空的百分比表示。图一:我国某地区多年平均云量日
- 7某兴趣小组想研究温度对某蔬菜新品种产量的影响,将实验结果绘制成如图曲线。据此提出的以下结论中,你认为合理的是:[
- 8汽车以36km/h的速度行驶,要求在紧急刹车时能在2s内停下来,则刹车时的加速度大小至少是多少?
- 9完形填空。 Many people could not forget the wonderful dance "
- 10下列有关叙述中,不正确的是[ ]A.激素经靶细胞接受并起作用后会被灭活,所以体内需要不断产生激素 B.膜外局部电
热门考点
- 1现有两杯20℃时的食盐饱和溶液,甲为500g,乙为1000g,在温度不变的情况下分别蒸发掉15g水,析出食盐晶体的质量分
- 22006年7月1日,青藏铁路全线试运行,首次开通四列旅游专线。关于入藏游的说法不正确的是 A.须做好氧气的供应设备B.须
- 3已知二次函数的图象如图,有下列结论:①b2-4ac>0;②abc>0;③8a+c>0;④9a+3b+c>0,其中,正确的
- 4(1)一种游标卡尺,它的游标尺有50个等分度,总长度为49mm.现用它测量某工件宽度,示数如图甲所示,其读数为_____
- 5要实现黄土高原社会、经济的可持续发展,关键是[ ]A.提高粮食产量B.大力发展经济C.大力加强基础设施建设D.加
- 6.Our strong sympathy for the people in the earthquake-strick
- 7一辆摩托车在平直的公路上以恒定的加速度启动,已知摩托车的额定功率为10kw,人和车的总质量为200kg。设行使中受到的阻
- 8—What about going shopping together? —Sorry, I have a lot of
- 9下列句子中加线成语使用有误的一项是[ ]A.《庄子》丰富的想象力,及其汪洋恣肆、变幻莫测、挥洒自如的风格,对后世
- 10假定某高等生物体细胞的染色体数是10条,其中染色体中的DNA用3H―胸腺嘧啶标记,将该体细胞放入不含有同位素的培养液中连