Introductory Logic
Quiz #5
October 14, 2005
 
Name: ________________________
R. Hammack
Score: _________



1.
Write out the truth table for the following propositions.

(a) ( S • R ) ⊃ ( ~S ≡ R )

(
S
R
)
(
~
S
R
)
T
T
T
F
F
T
F
T
T
F
F
T
F
T
T
F
F
F
T
T
T
F
T
T
F
F
F
T
T
F
F
F



(b) ~( R • S )

~
(
R
S
)
F
T
T
T
 
T
F
F
T
 
T
T
F
F
 
T
F
F
F
 

2. Is statement (a) from Question 1 contingent, tautologous or self-contradictory?


CONTINGENT


3. Are statements (a) and (b) from Question 1 logically equivalent, contradictory, consistent or inconsistent? List all that apply.


LOGICALLY EQUIVALENT and CONSISTENT



4. Decide if the following argument is valid or invalid by writing out its truth table.

~(G • M)
M ∨ ~G

~G


~
(
G
M
)
/
M
~G
//
~
G
F
T
T
T
T
T
FT
F
T
T
T
F
F
F
F
FT
F
T
T
F
F
T
T
T
TF
T
F
T
F
F
F
F
T
TF
T
F

VALID, because in every line where the premises are both true (the 3rd and 4th) the conclusion is true also.