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1、xyxylFPOxyoEvaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.方程准线线焦点图图象Evaluation only.Evaluation only. Created with Asp
2、ose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.1、点:焦点2、线:准线3、距离焦点到准线的距离FMLOpyx到一个定点的距离和到一条定直线的距离的比等于常数e (e =1)的点的轨迹是抛物线。 2pM1Evaluation only.Evaluation only. Created
3、with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.练习:P64#3,41.已知抛物线y2=2x的焦点为F,点P 是抛物线上的动点,又有定点A(3,2) 则当|PA|+|PF|取得最小值时,求 点P的坐标. 2.一动圆的圆心在抛物线y2=8x上,且 动圆恒与直线x+2=0相
4、切,则动圆必 经过定点: .Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.FMLOyx1、范围2、对称性3、顶点4、离心率Evaluation only.Evaluation only.
5、 Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.例1求顶点在原点，对称轴是坐标轴，并且经过点 的抛物线方程练习求适合下列条件的抛物线方程1、过点（3 , 2）2、焦点在直线x-2y-4=0上书P63例2(实际应用题)Evaluation only.Ev
6、aluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.图图形相 同 点定义义顶顶点离心率 不同点方程焦点准线线范围围对对称轴轴平面内，到定点距离与到定直线距离相等的点的轨迹原 点即(0，0) e=1 y2=-2pxx2=2pyx2
7、=-2pyx0，yRx0，yRy0，xRy0，xRx轴y轴y2=2pxEvaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.作业P69 练习题#1,3P70 习题A#6Evaluation on
8、ly.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.例2斜率为1的直线经过抛物线y2=5x 的焦点F，且与抛物线交于A、B两点，求线段AB的长。FAOyxBEvaluation only.Evaluation only
9、. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.练习1、已知抛物线的顶点在原点，焦点在x轴上，且截直线2x-y+1=0的弦长为 ，求抛物线方程。2、已知抛物线的顶点在原点，焦点在y轴上，抛物线上一点(m,-3)到焦点的距离为5 , 求抛物线方程。Ev
10、aluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.xyxylFPOxyoEvaluation only.Evaluation only. Created with Aspose.Slides f
11、or .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.图图形相 同 点定义义顶顶点离心率 不同点方程焦点准线线范围围对对称轴轴平面内，到定点距离与到定直线距离相等的点的轨迹原 点即(0，0) e=1 y2=-2pxx2=2pyx2=-2pyx0，yRx0，yRy0，xRy0，xRx轴y轴y2=2pxEvaluati
12、on only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.1.抛物线 3x+2y2=0的范围是 焦点是 . 顶点是 准线方程是 . 2.顶点在坐标原点，焦点是圆x2 + y2 =4x的圆心的抛 物线方程是 .x0,
13、 yR （0，0） y2 =8x1. 经过抛物线 y2 =2px的焦点F，作一条直线垂直2. 于它的对称轴，和抛物线相交于P1、P2 两点，3. 线段P1P2 叫做抛物线的通径.求通径P1P2的长.巩固练习例题分析Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Lt
14、d.Copyright 2004-2011 Aspose Pty Ltd.3. 动圆M经过点A( 3 , 0 )，且与直线 l: x =-3相切， 求动圆圆心M的轨迹方程.( y2 =12x )2. 探照灯反射镜的纵断面是抛物线的一部分.灯口直径 是 60 cm，灯深40cm. 求抛物线的标准方程和焦点的 位置.AB.yxFOEvaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5
15、Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.2*.抛物线y2=2px(p0)上有一动点A，A在x 轴上的射影是M ，N是AM的中点，NQ与抛物线的对称轴平行且交抛 物线于Q，直线MQ交y轴于T.求点N的轨迹方程； |OT|:|AM|1.图中是抛物线形拱桥，当水 面在L时，拱顶离水面2米，水 面宽4米。 水下降1米后，水面 宽多少？Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.一顶点在原点，焦点在X轴上的抛物线截直线2x-y-4=0所得的弦 长为3 ，求抛物线的方程。分析：本题可用待定系数法，设出抛物线的方程，由弦 长公式求出待定系数，从而确定抛物线方程。Evaluation only.Evaluation only
