On Thursday, September 27th we’ll have a quiz on Logic.

For this quiz you should know how to symbolize the logical structure of a statement, how to show that an argument is valid/invalid, and how to show that a statement is a tautology/contradiction. You should also know the definitions of the relevant logical terminology.

Here are the questions we discussed in class today. If you didn’t get a chance to complete them in class, work on these before the quiz. If you can answer these questions, you should be well prepared for the quiz!

- Symbolize the argument below and use truth tables to show that it is
**invalid**.

P1: If it’s raining outside then Dr. McDonald will have his umbrella.

P2: It is not raining outside.

C: Dr. McDonald does not have his umbrella.
- Prove that the following argument form is valid.

\[\begin{eqnarray}A\to B\\ B\to C\\ \overline{A \to C}\end{eqnarray}\]
- Is the argument form below valid or invalid? Prove your answer.

\[\begin{eqnarray}(A\wedge B)\to C\\ \overline{A \to (B \to C)}\end{eqnarray}\]