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[几何] 2015全国理2第11题

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乌贼 posted 2015-6-8 14:51 |Read mode
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我计算出来是$\dfrac{\sqrt3+1}{2}$

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kuing posted 2015-6-8 14:58
如果AB是焦点那就显然是你的结果,但这里AB可是顶点喔

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original poster 乌贼 posted 2015-6-8 15:02
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$AC=2a=2,AB=2c=\sqrt3+1$

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original poster 乌贼 posted 2015-6-8 15:06
回复 2# kuing

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kuing posted 2015-6-8 15:08
回复 4# 乌贼

没事,我第一眼也看错了

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kuing posted 2015-6-8 15:15
熟知结论:设 $A$, $B$ 是双曲线 $x^2/a^2-y^2/b^2=1$ 上关于其中心对称的两点,$P$ 为双曲线上任意一点,当 $k_{PA}$, $k_{PB}$ 均存在时,$k_{PA}k_{PB}=b^2/a^2$。
于是对于本题有 $b^2/a^2=1$。
活着&存在 posted 2015-6-8 15:50
未命名.JPG

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original poster 乌贼 posted 2015-6-8 19:59
回复 7# 活着&存在
正解

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original poster 乌贼 posted 2015-6-8 20:01
回复 6# kuing
熟知结论

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isee posted 2015-6-8 20:40
不能在简单了,D。你算错了……

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isee posted 2015-6-8 20:40
回复  kuing
熟知结论
乌贼 发表于 2015-6-8 20:01

    是真的,包括椭圆,课本后的练习结论,常用的武器。

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kuing posted 2015-6-9 02:02
回复 11# isee

不好意思,现在才看到你的回复要审核,下次回复进入审核时给我发个发消息通知一下

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original poster 乌贼 posted 2015-6-9 02:08
回复 12# kuing
还有这事

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kuing posted 2015-6-9 02:11
回复 13# 乌贼

嗯……敏、感、词……

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