问题
填空题
设集合A={1,2,3,4},B={4,5},则满足S⊆A且S∩B≠ϕ的集合S的个数为______.
答案
由题意,S中一定含有4,
∵A={1,2,3,4},S⊆A
∴S={4},{1,4},{2,4},{3,4},{1,2,4},{1,3,4},(2,3,4),{1,2,3,4}
故满足S⊆A且S∩B≠ϕ的集合S的个数为8个
故答案为:8
设集合A={1,2,3,4},B={4,5},则满足S⊆A且S∩B≠ϕ的集合S的个数为______.
由题意,S中一定含有4,
∵A={1,2,3,4},S⊆A
∴S={4},{1,4},{2,4},{3,4},{1,2,4},{1,3,4},(2,3,4),{1,2,3,4}
故满足S⊆A且S∩B≠ϕ的集合S的个数为8个
故答案为:8