Mathematical Logic And Boolean Algebra Question 69

Question: $ (p\wedge \tilde{\ }q)\wedge (\tilde{\ }p\wedge q) $ is

Options:

A) A tautology

B) A contradiction

C) Both a tautology and a contradiction

D) Neither a tautology nor a contradiction

Show Answer

Answer:

Correct Answer: B

Solution:

[b] $ (p\wedge \tilde{\ }q)\wedge (\tilde{\ }p\wedge q)=(p\wedge \tilde{\ }q)\wedge (\tilde{\ }q\wedge q) $ $ =f\wedge f=f $ (By using associative laws and commutative laws)
$ \therefore (p\wedge \tilde{\ }q)\wedge (\tilde{\ }p\wedge q) $ is a contradiction.