1, Briefly explain how the "deduction method" technique from section 1.2 is justified by the truth table that defines the implication operator ().

2, In lecture, we've discussed two different ways to prove that a statement is a tautology:

For any statement P, we can calculate the truth table for P, and if the result is True in all rows, then P is a tautology. This is the subject of section 1.1 in the book.

For any statement of the form P Q, we can use the numbered-list proof style to show that P Q is a tautology. This is the subject of section 1.2 in the book.

Briefly explain why the numbered-list proof style is important even though the truth table method is theoretically "just as good" for proving all of the tautologies that we've seen so far.