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集合是高中数学第一章节内容,集合是数学工具,学好集合、用好集合为后续的数学学习起到很关键的作用。我们可以从集合的元素、集合的运算、集合的特殊点、集合的易错点四个方面有效的掌握集合。一、抓住元素特征例1:已知集合A={a-2,2a2+5a,12},且-3∈A,求A。切入思维:由-3∈A,得-3=a-2或-3=2a2+5a,求出a后再进行验证。
The collection is the first chapter of high school mathematics content, the collection is a mathematical tool, learn to collect a good collection for the follow-up of mathematical learning plays a key role. We can effectively grasp the collection from the elements of the collection, the operations of the collection, the special points of the collection, and the easy-to-make points of the collection. First, grasp the element characteristics Example 1: Known set A = {a-2, 2a2 + 5a, 12}, and 3∈A, seeking A. Cut into the thinking: from -3 ∈ A, was -3 = a-2 or -3 = 2a2 +5 a, and then verify a.