(1)根据题意,若A={1,2,3},B={3,4},
则A∩B={3},
又由全集U={1,2,3,4},则∁ UB={1,2},
(2)A={1,2,3},
其子集有{1}、{2}、{3}、{1,2}、{1、3}、{2,3}、{1,2,3}、∅.
(1)根据题意,若A={1,2,3},B={3,4},
则A∩B={3},
又由全集U={1,2,3,4},则∁ UB={1,2},
(2)A={1,2,3},
其子集有{1}、{2}、{3}、{1,2}、{1、3}、{2,3}、{1,2,3}、∅.