高中数学必修2第2章抛物线的参数方程知识点
2017-06-14
在高中数学遇到需要解决的与抛物线有关的问题时,同学们需要牢记它的方程,下面是小编给大家带来的高中数学必修2第2章抛物线的参数方程知识点,希望对你有帮助。
高中数学抛物线的参数方程知识点(一)
抛物线方程
1 设,抛物线的标准方程、类型及其几何性质:
图形
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焦点
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准线
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范围
对称轴轴轴
顶点 (0,0)
离心率
焦点
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注:①顶点
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.
②则焦点半径
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;则焦点半径为
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.
③通径为2p,这是过焦点的所有弦中最短的.
④(或)的参数方程为
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(或
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)(为参数).
高中数学抛物线的参数方程知识点(二)
抛物线的性质(见下表):
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抛物线的焦点弦的性质:
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关于抛物线的几个重要结论:
(1)弦长公式同椭圆.
(2)对于抛物线y2=2px(p>0),我们有P(x0,y0)在抛物线内部
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P(x0,y0)在抛物线外部
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(3)抛物线y2=2px上的点P(x1,y1)的切线方程是
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抛物线y2=2px(p>0)的斜率为k的切线方程是y=kx+
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(4)抛物线y2=2px外一点P(x0,y0)的切点弦方程是
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(5)过抛物线y2=2px上两点
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的两条切线交于点M(x0,y0),则
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(6)自抛物线外一点P作两条切线,切点为A,B,若焦点为F,
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又若切线PA⊥PB,则AB必过抛物线焦点F.