| p | q | ~ p | ~ p V q |
-------------------------
| | | | |
| | | | |
| | | | |
| | | | |
Under all the letters p put TTFF
| p | q | ~ p | ~ p V q |
-------------------------
| T | | T | T |
| T | | T | T |
| F | | F | F |
| F | | F | F |
Under all the letters q put TFTF
| p | q | ~ p | ~ p V q |
-------------------------
| T | T | T | T T |
| T | F | T | T F |
| F | T | F | F T |
| F | F | F | F F |
Under all the negation symbols ~ put the opposite of what follows it:
| p | q | ~ p | ~ p V q |
-------------------------
| T | T | F T | F T T |
| T | F | F T | F T F |
| F | T | T F | T F T |
| F | F | T F | T F F |
Erase what was under the letter that followed the ~
(You don't have to erase it, but it keeps you from
getting mixed up, because you don't use it again.
You can also just mark through them:
| p | q | ~ p | ~ p V q |
-------------------------
| T | T | F | F T |
| T | F | F | F F |
| F | T | T | T T |
| F | F | T | T F |
Under the V put F only between TWO F's, otherwise put T
| p | q | ~ p | ~ p V q |
-------------------------
| T | T | F | F T T |
| T | F | F | F F F |
| F | T | T | T T T |
| F | F | T | T T F |
Then erase the ones on each side of the last column you filled in:
| p | q | ~ p | ~ p V q |
-------------------------
| T | T | F | T |
| T | F | F | F |
| F | T | T | T |
| F | F | T | T |
You teacher might want you to leave all those columns and not erase them.
But if so, I would line through them lightly.
The final answer is TFTT.
Edwin
Here are all the ways to have two combos of either T or F
TT
TF
FT
FF
Note how the first column has TT then FF
The second column alternates TFTF
So this is how we form the columns for p and q
p
q
~p
~p V q
T
T
T
F
F
T
F
F
Then we negate the first column of values. This means we flip from T to F and vice versa. This gets us the column of ~p truth values.
p
q
~p
~p V q
T
T
F
T
F
F
F
T
T
F
F
F
Then we apply the disjunction operation to the columns of ~p and q
The result of a disjunction is false only when both ~p and q are false; otherwise, the result is true