If A and B are true statements and X and Y are false statement , find out whether compound statements are true .For example:

(AÉ B) · ( X É Y )

Solution: (AÉ B) · ( X É Y )

(TÉ T) · ( F É F)

T · T

T Ans.

Another Examples:

1. X É ( X É Y )

2. (X É X ) É Y

3. A É ( X É B )

4. (A É B) É (~A É ~B )

II.Determine the validity and invalidity of the following Compound statements: In deductive logic, it is assumed that if the premises are true the conclusion must be true. In this wewill draw truth-table and by this we can determine the validity and invalidity of the givenstatements. And also give justification for this. For Example: pÉq /\ q

Solution: pÉq/\ q

Statement Conclusion

p

q

p É q

q

T

T

T

T

T

F

F

F

F

T

T

T

F

F

T

F

Ans. Invalid, because in the fourth row the table conclusion is the false although the premise is true.

For example:

1. p É q /\ ~q É ~p

2. p É q

pÚq /\ q

3. If Mohan goes to Meerut, then Sohan goes to Delhi. Sohan goes to Delhi. Therefore, Mohan goes to Meerut.