How to make truth table I have
$F(p, q) = (p \land q) \lor (\lnot p \land q)$
and i need to prove that
$\lnot F(\lnot p, \lnot q) \Leftrightarrow F(p, q)$
is not tautology.
I made truth table for $F(p, q)$ and it looks like this:
$$ 
\begin{array}{c||c||c}
p & q & F(p,q)\\
\hline
\top & \top & \top\\
\hline
\top & \bot & \bot\\
\hline
\bot & \top &\top\\
\hline
\bot & \bot &\top\\
\end{array} 
$$
After simplifying $\lnot F(\lnot p, \lnot q)$ i got
$\lnot F(\lnot p, \lnot q) = (p \lor q) \land (\lnot p \lor q)$ .
Now, I am not sure how to make truth table for this and how to compare these two.

You found out that $\neg F(\neg p, \neg q) = (p \lor q) \land (\neg p \lor q)$, so now simply extend your truth table:
$$ 
\begin{array}{c||c||c||c}
p & q & F(p, q) = (p \land q) \lor (\lnot p \land q) & \neg F(\neg p, \neg q) = (p \lor q) \land (\neg p \lor q)\\
\hline
\top & \top & \top & ?\\
\hline
\top & \bot & \bot & ?\\
\hline
\bot & \top &\top & ?\\
\hline
\bot & \bot &\top & ?\\
\end{array} 
$$
If the two columns $F(p,q)$ and $\neg F(\neg p, \neg q)$ have the same entries, then $F(p,q) \iff \neg F (\neg p, \neg q)$ is a tautology, otherwise it is not.
