Unn的知识精选

设*U={n|n∈N*且n≤9},A={2,5},B={1,2,4,5},则∁U(A∪B)中元素个数为(  ...
问题详情:设*U={n|n∈N*且n≤9},A={2,5},B={1,2,4,5},则∁U(A∪B)中元素个数为()A.4    B.5    C.6    D.7【回答】B解:∵A={2,5},B={1,2,4,5},∴A∪B={1,2,4,5},又∵*U={n|n∈N*且n≤9}={1,2,3,4,5,6,7,8,9},∴∁U(A∪B)={3,6,7,8,9},故∁U(A∪B)共有5...
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