4 供给与需求的市场力量(曼昆经济学原理微观).ppt

This is perhaps the most important chapter in the textbook. It’s worth mentioning to your students that investing extra time to master this chapter will make it easier for them to learn much of the subsequent material in the book. This is also one of the longest chapters in the textbook, and this PowerPoint file is one of the most graph-intensive. Many students taking economics for the first time have difficulty grasping the graphs, which are critically important in this and all subsequent chapters in the book. So an extra degree of hand-holding might be appropriate. Accordingly, this PowerPoint has carefully detailed animations that build many of the graphs with great care. For example, we show a demand or supply schedule next to the axes, and highlight each coordinate pair in the table as the corresponding point appears on the graph. Please be assured that the presentation of graphs is more streamlined in subsequent chapters. In this early chapter, though, we do not want to leave any students behind. If your students are already very comfortable with scatter-type graphs, you may wish to simplify or turn off the animation on these slides, in order to get through them faster. * In the real world, there are relatively few perfectly competitive markets. Most goods come in lots of different varieties—including ice cream, the example in the textbook. And there are many markets in which the number of firms is small enough that some of them have the ability to affect the market price. For now, though, we look at supply and demand in perfectly competitive markets, for two reasons: First, it’s easier to learn. Understanding perfectly competitive markets makes it a lot easier to learn the more realistic but complicated analysis of imperfectly competitive markets. Second, despite the lack of realism, the perfectly competitive model can teach us a LOT about how the world works, as we will see many times in the chapters that follow. * Demand comes fr