Chapter 2 Review Exercises
ex III

1. Which of the following pairs of sentences is a logically equivalent pair?
AvB , A&B
~(AvB) , ~A&~B
~(A&B) , ~~A&~~B
~(AvB) , ~Av~B

2. Which of the following is NOT true?
'John' has four letters.
'John' is the name of John.
'John' is equal to John.
'John' is equal to 'John'.

3. Which of the following is NOT a grammatically correct sentence of SL? (You may drop outside parentheses or use brackets instead of parentheses.) Note: We use ">" for our horseshoe and "=" in place of the triple-bar -- these may fail to display properly on some computers.
(Av(B>C))
~~Av(B>C)
(AvB>C)
(A>C)&(A>C)

4. Which of the following is NOT of the form ~P>~Q
~[(AvB)>~(CvD)]
~(AvB)>~(Cvd)
~(AvB)>~~(Cvd)
~~(AvB)>~(Cvd)

5. If "A" is true and "B" is false, which of the following is false?
A&~B
(~~Av~B)
(~Av~~B)
~A=B

Score =
Correct answers: