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1、双曲线的双曲线的 简单几何性质简单几何性质(3)(3)-直线与双曲线的位置关系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、直线与椭圆的位置关系：（2）弦长问题（3）弦中点问题（4）
2、经过焦点的弦的问题（1）直线与椭圆位置关系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.二、直线与双曲线位置关系种类：XYO种类:相离;相切;相交(两个交点,一个交点)Evaluatio
3、n 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.两个交点 一个交点 0 个交点相交 相 切相 交相离交点个数方程组解的个数有没有问题 ?Evaluation only.Evaluation only. Cr
4、eated 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 0 个交点和两个交点的情况都正常,那么 ,依然可以用判别式判断位置关系2一个交点却包括了两种位置关系:相切和相交 ( 特殊的相交 ) , 那么是否意 味着判别式等于零时 , 即可能相切也可能相 交 ? Ev
5、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.判断下列直线与双曲线之间的位置关系：12相 切相 交试一下:判别式情况如何?Evaluation only.Evaluation only. C
6、reated 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.一般情况的研究显然,这条直线与双曲线的渐进线是平行的, 也就是相交.把直线方程代入双曲线方程,看 看判别式如何?根本就没有判别式 !Evaluation only.Evaluation only. Creat
7、ed 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.当直线与双曲线的渐进线平行时 , 把直 线方程代入双曲线方程 , 得到的是一次方程 , 根本得不到一元二次方程 , 当然也就没有 所谓的判别式了 。 结论：判别式依然可以判断直线与双曲线的 位置关系 ！Evaluat
8、ion 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.判断直线与双曲线位置关系的操作程序把直线方程代入双曲线方程得到一元一次方程得到一元二次方程直线与双曲线的 渐进线平行相交（一个交点）计 算 判 别 式0=
9、00相交相切相离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.例1、判断下列直线与双曲线的位置关 系：相交(一个交点)相离Evaluation only.Evaluation only.
10、 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、设双曲线 与直线相交于不同的点A、B， 求双曲线C 的离心率e的取值范围.Evaluation only.Evaluation only. Created with Aspose.Slides fo
11、r .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.y. F2F1O.xEvaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides
12、 for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.y. F2F1O.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 Asp
13、ose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.y. F2F1OEvaluation 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.练习 .设设双曲线线则过则过
14、点M与双曲线线c有且只有一个交点的直线线共 有( ) A.2条 B.3条 C.4条 D.无数条的左准线线与x轴轴的交点是M,C数形结合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.xyo
15、. NMEvaluation 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.xyo. NMEvaluation only.Evaluation only. Created with Aspose.Slides
16、 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.xyo. NMEvaluation 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.Evaluation only.Evaluation only.
