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抛物线的直角弦定理

2014-03-19 16:23:02| 分类：几何学 | 标签： |举报 |字号大中小订阅

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（1）抛物线方程：y²=2px

（2）抛物线上一定点A：（x0，y0）

（3）直角弦：抛物线的一条弦关于A点的张角为直角

（4）抛物线的直角弦定理：

抛物线上一定点A的所有直角弦交于一点F(x1，y1)

x1=x0+2p

y1= -y0

（5）其直角弦端点切线的交点轨迹为F点关于抛物线的极线：

y1y=p( x+x1)

（6）极线上任意一点的切点弦经过极点。逆之，也成立。

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