# 高二数学理椭圆的几何性质课件-PPT课件

(3)

Evaluation only. eated with Aspose.Slides for .NET 3.5 Client Profile 5.2.0 Copyright 2019-2019 Aspose Pty Ltd.

2009年下学期

| MF | 1. 椭圆的第二定义： ?e Evaluation only. d eated with Aspose.Slides for .NET 3.5 Client Profile 5.2.0 2 2 2 a x y Copyright 2019-2019 Aspose Pty 2. 准线方程： x ? ? ( 2 ? 2Ltd. ? 1) c a b

2009年下学期

[练习]
x2 y2 1. 求椭圆 ? ? 1的右焦点和右 25 16 准线, 左焦点和左准线 . only. Evaluation 2. 椭圆 25 ? 16 ? 1上点M到左准线

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1. 焦半径 |MF|

Evaluation only. 焦点三角形：椭圆上任意一点与两 eated2. with Aspose.Slides for .NET 3.5 Client Profile 5.2.0 Copyright 2019-2019 Aspose Pty Ltd. 焦点所构成的三角形

|MF左|=a+ex0 |MF右|=a－ex0

S ?MF1F2 ? b ? tan
2

?
2

x y [例1] 已知F1 , F2是椭圆 ? ?1 100 64
Evaluation only. . 的两个焦点 , P是椭圆上任一点

2

2

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(1) 若?F1 PF2 ?

3

, 求?F1 PF2的面积;

( 2) 求 | PF1 | ? | PF2 | 的最大值 .

x y [例2] 已知点 A(1,2)在椭圆 ? 16 12

2

2

Evaluation only. 1内,Aspose.Slides F的坐标为(for 2,0.NET ), 在椭圆上求一点 eated? with 3.5 Client Profile 5.2.0 Copyright 2019-2019 Aspose Pty Ltd.

P使 | PA | ?2 | PF | 最小.

2009年下学期

x 2 [例3] 若Q在椭圆上 ? y ? 1移动, 4 Evaluation only. 2

2

eated with Aspose.Slides 3 for .NET 3.5 Client Profile 5.2.0 点P坐标为 (0, 2019-2019 ), 求PQ最值 . Pty Ltd. Copyright Aspose

2009年下学期

Evaluation only. 四、小结 eated with Aspose.Slides for .NET 3.5 Client Profile 5.2.0 Copyright 2019-2019 Aspose Pty Ltd.

2009年下学期