题目

已知集合A={x|﹣1≤x＜3}，B={x|2＜x≤5}，则A∪B=（　　）                        A．{x|2＜x＜3}            B．{x|﹣1≤x≤5}           C．{x|﹣1＜x＜5}        D．{x|﹣1＜x≤5} 答案：B 【考点】并集及其运算．                                                                          【专题】计算题．                                                                               【分析】分别把两集合的解集表示在数轴上，根据数轴求出两集合的并集即可                     【解答】解：把集合A={x|﹣1≤x＜3}，B={x|2＜x≤5}，                                   表示在数轴上：                                                                                                                                            则A∪B=[﹣1，5]．                                                                            故选B                                                                                                 【点评】本题考查了集合的基本运算，属于基础题．                                      

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