PHIL1012 – Introduction to Logic
Problem Set 3 – Second Semester, 2021
Submit your answers to Problem Set 3 via Canvas before 23:59, Wednesday of Week 6.
1. Use a tree to test whether the following argument is valid or invalid. If it is invalid, read off
a counterexample.
1. A → B
2. B →C
∴ A∨C
2. Use a tree to test whether the following argument is valid or invalid. If it is invalid, read off
a counterexample.
1. A ↔ B
2. ¬A
∴ ¬B
1