A = A U '('A U B)
I know how to prove A U '('A U B) but how do I prove the other side? Is this correct? Is it ok just to add 'B?
A /* identity laws */ A U Ø /*domination laws */ A U (Ø ∩ 'B) /* distributive laws */ (A U Ø) ∩ ( A U 'B) /*identity laws */ A ∩ ( A U 'B) /* distributive laws */ (A ∩ A) U (A ∩ 'B) /*idempotent laws */ A U (A ∩ 'B) /*de morgan's laws */ A U '('A U B)