过抛物线外一点
作抛物线的两条切线,两切点的连线段称为点
对应的切点弦.已知抛物线为
,点
,
在直线
上,过
,
两点对应的切点弦分别为
,
.
(1)当点
在
上移动时,直线
是否经过某一定点,若有,请求出该定点的坐标;如果没有,请说明理由.
(2)当
时,求线段
长度的最小值,及此时点
,
的坐标.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e42102c1c07562853219ca5918803a27.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d42502a5730e1930d77d7100d1e34707.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
(1)当点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f85fca60a11e1af2bf50138d0e3fe62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a77e3c1c236141d6118429fade0a9b9d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a5f1641947153c80b987320885a2b57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
更新时间:2021-03-06 10:45:03
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【推荐1】如图,一个湖的边界是圆心为O的圆,湖的一侧有一条直线型公路l,湖上有桥AB(AB是圆O的直径).规划在公路l上选两个点P,Q,并修建两段直线型道路PB,QA,规划要求:线段PB QA上所有点到点O的距均不小于圆O的半径.已知点A,B到直线l的距离分别为AC和BD(C,D为垂足),测得
(单位:百米).
![](https://img.xkw.com/dksih/QBM/2021/6/2/2734571357159424/2734874451542016/STEM/25305f017a1d4fd1a6ce4ec0fcf2dd46.png?resizew=199)
(1)若道路PB与桥AB垂直,求道路PB的长;
(2)在规划要求下,P和Q中能否有一个点选在D处?并说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/237b407dea87436ee3632eebd9f9116c.png)
![](https://img.xkw.com/dksih/QBM/2021/6/2/2734571357159424/2734874451542016/STEM/25305f017a1d4fd1a6ce4ec0fcf2dd46.png?resizew=199)
(1)若道路PB与桥AB垂直,求道路PB的长;
(2)在规划要求下,P和Q中能否有一个点选在D处?并说明理由.
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【推荐2】已知
的顶点
边上的高
所在直线方程为
,角
的平分线所在直线方程为
.
(1)求顶点
的坐标;
(2)求直线
的方程.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a466e8a3751a5bc53c707de04428d44.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/59b2caf6048aa0807d8ba591963ff6e2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1b979396a703fb14715ba39232f5786a.png)
(1)求顶点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
(2)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
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【推荐1】设抛物线
的方程为
,其中常数
,F是抛物线
的焦点.
(1)若直线
被抛物线
所截得的弦长为6,求
的值;
(2)设
是点
关于顶点O的对称点,
是抛物线
上的动点,求
的最大值;
(3)设
是两条互相垂直,且均经过点F的直线,
与抛物线
交于点
,
与抛物线
交于点
,若点G满足
,求点G的轨迹方程.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4bcd8ee2d8367c167d6ae0abc741b6b8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9fc58c62444bf42a25289c45425a00f2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5abd313d4e92a762fb7fb0c1cb65263d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4bcd8ee2d8367c167d6ae0abc741b6b8.png)
(1)若直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e55aa0a20848c37c1892c567b2315e04.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4bcd8ee2d8367c167d6ae0abc741b6b8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1010846eeec6c9da29640f5aa3f8738.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4bcd8ee2d8367c167d6ae0abc741b6b8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/269f88956dd0fc199ea0ab99bbb720e2.png)
(3)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e309450c31073115d57db69e6868d56c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e9b0f5f44abbc6544a2f672b025b013.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4bcd8ee2d8367c167d6ae0abc741b6b8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/01c74a907dda6bb7d9d56d009d9df253.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3f6f17bc385bafb37e8f964e5eb99cd0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4bcd8ee2d8367c167d6ae0abc741b6b8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/39acab3cfb59bfc9591371721ab01d93.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e9bc6dd620476873256079e86c7474f.png)
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【推荐2】设抛物线
,过
轴上点
的直线
与
相切于点
,且当
的斜率为
时,
.
(1)求
的方程;
(2)过
且垂直于
的直线交
于
两点,若
为线段
的中点,证明:直线
过定点.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7e6c830bfa9a1b979a1a9665166424bf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d053b14c8588eee2acbbe44fc37a6886.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f85fca60a11e1af2bf50138d0e3fe62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f85fca60a11e1af2bf50138d0e3fe62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f89eef3148f2d4d09379767b4af69132.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/da160ad8a0cddbbce70e760a1a96ff30.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
(2)过
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f85fca60a11e1af2bf50138d0e3fe62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7789a500686c7a73770404ead6af0590.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4aa0df7f1e45f9de29e802c7f19a4f64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5d7b816eca15d4b7d060013df53edd53.png)
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【推荐1】已知抛物线
,准线方程为
,直线
过定点
,且与抛物线交于
两点,
为坐标原点.
(1)求抛物线方程;
(2)
是否为定值,若是,求出这个定值;若不是,请说明理由;
(3)当
时,设
,记
,求
的最小值及取最小值时对应的
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b35f0b940c8422ef47edc3b7ce55e47.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4ca8e3b654909a9d5e1cf044fc3ee49d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f85fca60a11e1af2bf50138d0e3fe62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/456dc9e5dbcc3ffe05c82e1cfe0c1804.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/01c74a907dda6bb7d9d56d009d9df253.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
(1)求抛物线方程;
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/658aa70a197c830aa765f2f7ea4c86c5.png)
(3)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a2a51944c720568f35d443589dfc1aa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d392c79b0c9bf2ffa4bdd9d1bc877f2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/996c475d1e8a0811a12c10cb8cc54781.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0804cb0d462ffad2d780a4cac7a09ac4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df64046e91b047037f19e4032e3b6de3.png)
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【推荐2】已知抛物线
上一动点G,过点G作x轴的垂线,垂足为D,M是
上一点,且满足
.
(1)求动点M的轨迹C的方程;
(2)若
为曲线C上一定点,过点P作两条直线分别与抛物线交于A,B两点,若满足
,求证:直线
恒过定点,并求出定点坐标.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7ca3b0aa32a947786e56e03358ed019d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce8f887360a533f0a25b0b34fb11f0a1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e5c8f133f8a3560ff5a14137411740f2.png)
(1)求动点M的轨迹C的方程;
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4be3a55efb9e423e27ca1e6a43881788.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c48d7f0077a502851589b8c9fc608e10.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
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