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随着近几年高考的变知识立意为能力立意,而不再强调对知识点的履盖面,一些只需要“了解”的概念也常为高考和其他选拔性考试的题目.其中“映射”的概念就是如此.映射是指两个非空集合A,B之间的一种对应法则,即A中任何一个元素,在B中都有唯一的元素与之对应,其中集合B为象集合,集合A为原象集合.理解映射的概念要注意下面几个要点①f:A→B有方向性;②A中每一个元素都在B中有唯
With the change of the knowledge of the college entrance examination in recent years as the ability to develop ideas, but no longer emphasize the coverage of knowledge points, some only need to understand the concept of “examination” is often the subject of college entrance examination and other selective examination. The concept of “mapping” is the same. Mapping refers to a correspondence between two non-empty sets A, B, that is, any element in A, in B has a unique element corresponding to it, which set B For image collections, set A is a collection of primitives. To understand the concept of mapping, note the following points: 1f: A→B has directionality; 2A has every element in B.