Question

设全集U={x||x|小于4,且x属于Z},S={-2,1,3},若CuP包含于S,则这样的集合P共有几个?

Answer 1

1U={x|x=-3,-2,-1,0,1,2,3}

2CuP包含于S,因为S的子集有{-2,1}、{-2,3}、{1,3}、{-2}、{1}、{3}、{-2,1,3}、空集

3又因为CuP包含于S,所以P可以为{-3,-1,0,2,3}、{-3,-1,0,1,2}、{-3,-2,-1,0,2}、{-3,-1,0,1,2,3}、{-3,-2,-1,0,2,3}、{-3,-2,-1,0,1,2}、{-3,-1,0,2}、{-3,-2,-1,0,1,2,3}共8个