1、A级基础巩固1.(全国卷)若集合U=1,2,3,4,5,6,7,A=2,3,4,5,B=2,3,6,7,则B(UA)=()A.1,6 B.1,7C.6,7 D.1,6,7答案:C2.若集合A=1,5,7,B=xZ|1x7,则BA=()A.2,4,6 B.2,3,4C.2,3,4,6 D.2,3,4,7答案:C3.若全集U=1,2,3,4,5,6,7,8,集合A=1,2,3,4,B=2,4,6,8,则(UA)(UB)=()A.5,7 B.1,5,7C.2,4 D.1,2,3,4,6,8答案:A4.若全集U=R,集合A=x|x3,或x0,则UA=x|0x3.5.已知全集U=x|x4,集合A=x|-
2、2x3,B=x|-3x2,求AB,(UA)B,A(UB).解:因为U=x|x4,A=x|-2x3,B=x|-3x2, 所以UA=x|x-2,或3x4,UB=x|x-3,或2x4,AB=x|-2x2,所以(UA)B=x|x2,或3x4,A(UB)=x|2x2.(1)求AB,(RB)A;(2)若集合C=x|1x2,所以AB=x|2x3,RB=x|x2,所以(RB)A=x|x2x|1x3=x|x3.(2)因为集合C=x|1x1,a3,解得1a3.综上,a的取值范围是a3.C级挑战创新9.多选题若集合A=x|1x4,B=x|x0,则下列结论正确的是()A.AB=B.AB=x|1x4C.(RA)B=x|x1D.(RB)A=x|x0解析:因为集合A=x|1x4,B=x|x4,RB=x|x0,所以AB=,AB=x|x0,或1x4,(RA)B=x|x0,(RB)A=x|x0.答案:AD10.多选题若集合M=x|-3x1,N=x|x3,则集合x|x-3,或x1=()A.MNB.RMC.R(MN)D.R(MN)解析:因为集合M=x|-3x1,N=x|x3,所以MN=x|-3x3.答案:BC
