3. Formal Logic

Formal Proofs — Quiz

Test your understanding of formal proofs with 5 practice questions.

Practice Questions

Question 1

In a formal proof, which rule allows you to infer $ \neg P $ from $ P \rightarrow Q $ and $ \neg Q $?

Question 2

Which of the following is the correct next step in a proof given the premises: 1. $ P \rightarrow Q $, 2. $ Q \rightarrow R $, and 3. $ P $?

Question 3

What does the rule of Conjunction Introduction allow you to do in a formal proof?

Question 4

In a formal proof, which rule justifies concluding $ Q \lor P $ from $ P $?

Question 5

Which inference rule allows you to derive $ R $ from the premises $ P \rightarrow Q $ and $ Q \rightarrow R $ and the statement $ P $?