设集合A={1,2,3},集合B={1,2,4,5},A∩B=( )A.{1,2,3,4,5}B.{1,2}C...答:∵集合A={1,2,3},集合B={1,2,4,5},∴集合A∩B={1,2}.故选B.
设集合A={1,2,3},B={2,3,4},则A∪B=( ) A.{1,2,3,4} B.{1,2,3} C...答:∵A={1,2,3},B={2,3,4},∴A∪B={1,2,3,4}故选A.
设集合A={1,2,3},B={2,3,4},则A∪B=( ) A.{1,2,3,4} B.{1,2,3} C...答:∵A={1,2,3},B={2,3,4},∴A∪B={1,2,3,4}故选A.