CIS 125

8 DeMorgans Law


Note: The tilde (~) is used to denote a logical inversion, or NOT, operation.

The symbol v is used to represent the OR operator, while the ^ symbol represents the AND operator.


For problems 1-4, use truth tables to determine if each pair of propositions are equivalent


1. (p ^ q)

p v q

e.g. is (p ^ q) equivalent to p v q for every combination of truth values of p and q?










2. (p ^ q)

p v q










3. (p v q)

p ^ q










4. p ^ q

(p v q)










For problems 5-8 attempt to simplify the expression by applying DeMorgans law.


5. (p v q)





6. (p v q)





7. p ^ (q v r)





8. (p v q) ^ r