传统集合运算实例.doc

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1、__________________________________________________课堂练习（二）1.设有关系R和S,如图所示RABC367257723423SABC345723计算：R∪SR-SR∩SR×SΠ3，2(S)σB＜’5’(R)1.R∪SABC3453672577234232.R-S____________________________________________________________________________________________________ABC3453.R∩SABC7234.R×SR.AR.

2、BR.CS.AS.BS.C3673453677232573452577237233457237234233454237235.Π3，2(S)BC45236.σB＜’5’(R)ABC723____________________________________________________________________________________________________423__________________________________________________