The given circuit is equivalent to:

If $p$: It is raining and $q$: It is pleasant,then the symbolic form of "It is neither raining nor pleasant" is

Consider statements $p: S_1$ is closed; $q: S_2$ is closed; $r: S_3$ is closed. The simplified equivalent circuit diagram and its logical statement for the switching circuit is respectively.

The negation of $\sim s \vee (\sim r \wedge s)$ is equivalent to :

The contrapositive of the statement pattern $[p \lor (p \to q)] \to (p \land \sim q)$ is

The negation of the contrapositive of the statement pattern $(p \vee \sim q) \rightarrow (p \wedge \sim q)$ is