~(πβπ) β‘ πβ§βΌπ π|π|πβπ|~(πβπ)|βΌπ|πβ§βΌπ|~(πβπ)β‘πβ§βΌπ| T|T| T |F |F | F | T | T|F| F |T |T | T | T | F|T| T |F |F | F | T | F|F| T |F |T | F | T | This is true in all 4 cases, so it's called a tautology". Rules (You should learn them). ~ means to change what follows ~ to F if it's T, and to T if it's F. β means to put T in all cases except when there's a T on the left of β and an F on the right of β. β‘ means to put a T if the same letter (T or F) is on both sides of β‘. β§ means to put an F unless there are T's on both sides, then you put T. v means to put a T unless there are F's on both sides, then you put F (There were none of these v in this problem.) Edwin