Mathematical Logic And Boolean Algebra Question 18

Question: The following statement $ (p\to q)\to [(\tilde{\ }p\to q)\to q] $ is

Options:

A) a fallacy

B) a tautology

C) equivalent to $ \tilde{\ }p\to q $

D) equivalent to $ p\to \tilde{\ }q $

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Answer:

Correct Answer: D

Solution:

[d] $ \tilde{\ }s\vee (\tilde{\ }r\wedge s)=(\tilde{\ }s\vee \tilde{\ }r)\wedge (\tilde{\ }s\vee s) $ $ =\tilde{\ }(\tilde{\ }s\wedge r)\wedge t $ $ =\tilde{\ }(s\wedge r) $ So, negation is $ s\wedge r $ .