this course will help you gain the ideas, owledge and skills you need to write fundraising copy that produces more impressive and profitable results.第一章 1.1 1.1.2 集合间的基本关系
1.集合{0}与?的关系是( ) A.
?
B.{0}∈? D.{0}??
C.{0}=?
解析:空集是任何非空集合的真子集,故选项A正确.集合与集合之间无属于关系,故选项B错误;空集不含任何元素,{0}含有一个元素0,故选项C、选项D均错误.
答案:A
2.设A={x|-1
B.B∈A D.BA
解析:∵-1 3.集合{a,b}的子集个数为( ) A.1 C.3 B.2 D.4 B. 解析:当子集不含元素时,即为?;当子集中含有一个元素时,其子集为{a},{b};当子集中有两个元素时,其子集为{a,b}. 答案:D 4.集合U,S,T,F的关系如图所示,下列关系错误的有________.(填序号) ①S④SU;②FT;③ST; F;⑤SF;⑥FU. 解析:根据子集、真子集的Venn图,可知SU,ST,FU正确,其余错误. 答案:②④⑤ 5.用适当的符号填空(“∈、?、、=”). (1)a________{a,b,c}; (2)?________{x∈R|x+1=0}; (3){0}________{x|x=x}; (4){2,1}________{x|x-3x+2=0}. 解析:(1)为元素与集合的关系,(2)(3)(4)为集合与集合的关系.易知a∈{a,b,c}; ∵x+1=0在实数范围内的解集为空集, 故?={x∈R|x+1=0}; 1 2 2 222 this course will help you gain the ideas, owledge and skills you need to write fundraising copy that produces more impressive and profitable results.∵{x|x2 =x}={0,1},∴ x|x2=x}; ∵x2 -3x+2=0的解为x1=1,x2=2. ∴{2,1}={x|x2 -3x+2=0}. 答案:(1)∈ (2)= (4)= 6.已知集合A={x,xy,x-y},集合B={0,|x|,y}.若A=B,求x+y的值. 解:∵0∈B,A=B,∴0∈A.又由集合中元素的互异性,可以断定|x|≠0,y≠0, ∴x≠0,xy≠0.故x-y=0,即x=y. 此时A={x,x2, 0},B={0,|x|,x}, ∴x2 =|x|.当x=1时,x2 =1,与元素互异性矛盾, ∴x=-1,即x=y=-1. ∴x+y=-2. 2