Demonstrate De Morgan's second law: (A∩B)c=?(A \cap B)^c = ?(A∩B)c=?
A∩BA \cap BA∩B
Ac∪BcA^c \cup B^cAc∪Bc
Ac∩BcA^c \cap B^cAc∩Bc
A∪BA \cup BA∪B