- Use the truth-tree method to determine whether the following argument is truth-functionally valid or invalid. If it is invalid, recover a
truth-value assignment that shows this. (10 marks)
P1 (J T) J
P2 (T J) T
C ⇠J _ ⇠T - Use a truth tree to determine whether the sentence
([(C D)&(D E)] & C) & ⇠E
is truth-functionally true, truth-functionally false or truth functionally
indeterminate. (10 marks) - Using SD, derive D & ⇠D from {(⇠A & B) (B ⌘ D), B (C & ⇠A),
⇠D & B}. (10 marks) - Using SD, demonstrate that (A & C) _ (B & C) follows from
(A _ B) & C. (10 marks) - Using SD, demonstrate that A [B (A B)] is a theorem. (10
marks)
Sample Solution
