(理)(2011·安徽省“江南十校”联考)已知集合P={3,log2a},Q={a,b},若P∩Q={0},则P∪Q等于( )
A.{3,0} C.{3,0,2} [答案] B
[解析] 根据题意P∩Q={0},所以log2a=0, 解得a=1从而b=0,可得P∪Q={3,0,1},故选B.
4.(文)(2011·山东文,1)设集合M={x|(x+3)(x-2)<0},N ={x|1≤x≤3},则M∩N =( )
A.[1,2) C.(2,3] [答案] A
[解析] 由(x+3)(x-2)<0知-3<x<2,所以M∩N=[1,2),解答此题要特别注意区间端点能否取到.
(理)(2011·福建龙岩质检)已知集合M={x|x+1≥0},集合N={x|x2+x-2<0},则M∩N=( )
A.{x|x≥-1} C.{x|-1<x<1} [答案] D
[解析] ∵M={x|x≥-1},N={x|-2<x<1}, ∴M∩N={x|-1≤x<1},∴选D.
5.(文)(2011·湖北文,1)已知U={1,2,3,4,5,6,7,8},A={1,3,5,7},B={2,4,5},则 U(A∪B)=( )
A.{6,8} C.{4,6,7}
B.{5,7} D.{1,3,5,6,8} B.{x|x<1} D.{x|-1≤x<1} B.[1,2] D.[2,3] B.{3,0,1} D.{3,0,1,2}