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{(4,-1)} (4,-1) {4、-1}
{3,–1} 3,–1 (3,–1) {(3,–1)}
={y|y=2x,x<0}, ={y|y=log2x},则A.∩B.=( ) A.{y|y>0}B.{y|y>1} {y|0∅
x=3,y=-1 (3,-1) {(3,-1)} {3,-1}
={(x,y)|x,y为实数,且x2+y2=1}, ={(x,y)|x,y为实数,且x+y=1},则A.∩B.的元素个数为( ). A.4B.3 2 1
={(x,y)|x,y为实数,且x2+y2=1}, ={(x,y)|x,y为实数,且x+y=1},则A.∩B.的元素个数为( ). A.4B.3 2 1
={x|0≤x≤2}, ={y|0≤y≤4},下列对应关系不能构成从集合A.到集合B.的映射的是( ) A.y=2xB.y=x y=x2 y=4x-1
={(x,y)|x,y是实数,且x2+y2=1}, ={(x,y)|x,y是实数,且y=x},则A.∩B.的元素个数为( ). A.0B.1 2 3
={(x,y)|x,y为实数,且x2+y2=1}, ={(x,y)|x, y为实数,且x+y=1},则A.∩B.的元素个数为 ( ) A.4B.3 2 1