Hi everyone,

Could someone please help me on this proof?

Find a statement form, S, equivalent to -(P V Q) and show that it is logically equivalent by constructing the truth table for "S if and only if -(P V Q)" and showing that this statment form is a tautology.

My attempt:

A tautology for -(P V Q) is -P^-Q and a tautology for -P V -Q is -(P ^ Q)

P Q -P ^-Q -P ^-Q

T T I'm not sure what the last two columns would be. Could someone please explain it to me?
T F
F T
F F


The statement would be "If and only if she gets good grades she can go to the movies

Thank you very much