2014届高三数学一轮复习 (基础知识+小题全取+考点通关+课时检测)6.2一元二次不等式课件 新人教A版.ppt

Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 答案：C Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. * [知识能否忆起] 　 一元二次不等式的解集 二次函数的图像与对应的一元二次方程的根、一元二次不等式之间的关系可归纳为： Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 判别式 Δ＝b2－４aｃ Δ0 Δ＝0 Δ0 二次函数y＝ax2＋bx＋c (a0)的图象 一元二次方程ax2＋bx＋c＝0 (a≠0)的根 有两相异实根x＝x1或x＝x2 有两相同实根x＝x1 无实根 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 判别式 Δ＝b2－４aｃ 一元二次不等式的解集 ax2＋bx＋c0(a0) ax2＋bx＋c0(a0) Δ0 　 Δ＝0 　 Δ0 R {x|xx1或 xx2} {x|x1xx2} {x|x≠x1} ? ? 若a0时，可以先将 ，对照上表求解． 二次项系数化为正数 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. [小题能否全取] 1．(教材习题改编)不等式x(1－2x)＞0的解集是(　　) 答案：B Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 答案：B Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. A．(－1,1) B．(－2,2) C．(－∞，－2)∪(2，＋∞) D．(－∞，－1)∪(1，＋∞) 答案：C Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 答案：－1　1 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 答案：{x|x＜1，或x＞2} Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 解一元二次不等式应注意的问题： 　　(1)在解一元二次不等式时，要先把二次项系数化为正数． 　　(2)二次项系数中含有参数时，参数的符号会影响不等式的解集，讨论时不要忘记二次项系数为零的情况． 　　(3)解决一元二次不等式恒成立问题要注意二次项系数的符号． 　　(4)一元二次不等式的解集的端点与相应的一元二次方程的根及相应的二次函数图象与x轴交点的横坐标相同． Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. (2)x2－4ax－