[高一数学必修2直线的倾斜角与斜率用.ppt

高一新课标人教版 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 问题1：如何确定一条直线在直角坐标 系的位置呢？ 两点或一点和方向 问题2：如果已知一点还需附加什么条件，才能确定直线？ 一点和方向 问题3：如何表示方向？ 用角 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 直线的倾斜角 l α 我们取x轴为基准，x轴正向与直线L向上的方向之间所成的角α叫做直线L的倾斜角。 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 规定：当直线和x轴平行或重合时， 它的倾斜角为0° 1、直线的倾斜角 由此我们得到直线倾斜角α的范围为： Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. l1 l2 l3 看看这三条直线，它们倾斜角的大小关系是什么？ 想一想 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 想一想 你认为下列说法对吗？ 1、所有的直线都有唯一确定的倾斜 角与它对应。 2、每一个倾斜角都对应于唯一的一条直线。 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 　　日常生活中，还有没有表示倾斜程度的量？ 问题引入 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 2、直线的斜率 倾斜角是90 °的直线没有斜率。 描述直线倾斜程度的量——直线的斜率 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 应用： O x y Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 例2 直线 l1、 l２、 l３的斜率分别是k1、 k２、 k３，试比较斜率的大小 l1 l２ l３ Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 小结 1、倾斜角的定义及其范围 2、斜率的定义及斜率与倾斜角的相互转化 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. k=0 k 0 k不存在 k0 Evaluation only. Created with Aspose.Slides for .NET 3.5