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[几何] 抛物线与准线问题

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敬畏数学 posted 2024-10-23 09:29 |Read mode
$y ^2 =4x$的焦点为F,过D(-1.0)的直线交抛物线A、B,(1)BF为$\angle DFA $的平分线,求AD的斜率;(2)AF=2BF,求AD的斜率;

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kuing posted 2024-10-23 15:59
FA、FB 斜率互反

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original poster 敬畏数学 posted 2024-10-23 18:33
Last edited by 敬畏数学 2024-10-23 18:40谢谢!这个可以推广圆锥曲线都有:KAD/e=sinAFD=sinBFX,3年前高手都轻松做完。

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original poster 敬畏数学 posted 2024-10-23 18:34
敬畏数学 发表于 2024-10-23 18:33
谢谢!这个可以推广圆锥曲线都有:KAD/e=sinAFD=sinBFX
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original poster 敬畏数学 posted 2024-10-23 18:36
敬畏数学 发表于 2024-10-23 18:34
https://kuing.cjhb.site/forum.php?mod=viewthread&tid=7910
宝库中有一道类似宝题。

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