在集合运算中常常借助于数轴、Venn图来处理集合的运算,从而使问题得以简化,使运算快捷明了.一、集合的基本运算例1.已知集合A={x|x是平行四边形},B={x|x是矩形},C={x|x是正方形},D{x|x是菱形},则() In the collection of operations, often with the help of the number of axes, Venn diagram to deal with the operation of the set, so that the problem is simplified, so that the operation is quick and clear. First, the basic set of operations example 1 known set A = {x | x is a parallelogram} , B = {x | x is a rectangle}, C = {x | x is a square}, D {x | x is a diamond}