1、A级基础巩固一、选择题1(2018天津卷)设全集为R,集合Ax|0x2,Bx|x1,则A(RB)()Ax|0x1Bx|0x1Cx|1x2 Dx|0x2解析:全集为R,Bx|x1,则RBx|x1因为集合Ax|0x2,所以A(RB)x|0x1答案:B2已知三个集合U,A,B之间的关系如图所示,则(UB)A()A3 B0,1,2,4,7,8C1,2 D1,2,3解析:由Venn图可知U0,1,2,3,4,5,6,7,8,A1,2,3,B3,5,6,所以(UB)A1,2答案:C3(2019全国卷)已知集合A1,0,1,2,Bx|x21,则AB()A1,0,1 B0,1 C1,1 D0,1,2答案:A4
2、设集合Sx|x2,Tx|4x1,则(RS)T等于()Ax|2x1 Bx|x4Cx|x1 Dx|x1解析:因为Sx|x2,所以RSx|x2而Tx|4x1,所以(RS)Tx|x2x|4x1x|x1答案:C5已知全集U1,2,3,4,5,6,7,A3,4,5,B1,3,6,那么集合2,7是()AAB BABCU(AB) DU(AB)解析:因为AB1,3,4,5,6,故U(AB)2,7答案:D二、填空题6设集合U1,2,3,4,5,A1,2,3,B3,4,5,则U(AB)_解析:因为A1,2,3,B3,4,5,所以AB3,故U(AB)1,2,4,5答案:1,2,4,57设全集UxN*|x6,集合A1,
3、3,B3,5,则U(AB)_解析:UxN*|x61,2,3,4,5,AB1,3,5,所以U(AB)2,4答案:2,48设UR,已知集合Ax|x1,Bx|xa,且(UA)BR,则实数a的取值范围是_解析:因为Ax|x1,所以UAx|x1由Bx|xa,(UA)BR可知,a1.答案:a1三、解答题9设全集U2,3,a22a3,已知Ab,2,UA5,求实数a,b的值解:因为UA5,所以5U且5A.又bA,所以bU,由此得解得或经检验都符合题意10设全集为R,Ax|3x7,Bx|2x10,求RB,R(AB)及(RA)B.解:把集合A,B在数轴上表示如下:由图知RBx|x2,或x10,ABx|2x10,所
4、以R(AB)x|x2,或x10因为RAx|x3,或x7,所以(RA)Bx|2x3,或7x10B级能力提升1已知全集UR,集合Ax|x3,或x7,Bx|x3 Ba|a3Ca|a7 Da|a7解析:因为Ax|x3,或x7,所以UAx|3x3.答案:A2已知集合A0,2,4,6,UA1,1,3,3,UB1,0,2,则集合B_解析:因为UA1,1,3,3,A0,2,4,6,所以U1,1,0,2,4,6,3,3,又UB1,0,2,所以B1,4,6,3,3答案:1,4,6,3,33已知全集U不大于20的素数,M,N为U的两个子集,且满足M(UN)3,5,(UM)N7,19,(UM)(UN)2,17,求M,N.解:方法一U2,3,5,7,11,13,17,19,如图,所以M3,5,11,13,N7,11,13,19方法二因为M(UN)3,5,所以3M,5M且3N,5N.又因为(UM)N7,19,所以7N,19N且7M,19M.又因为(UM)(UN)2,17,所以U(MN)2,17,所以M3,5,11,13,N7,11,13,19