Question

Write the negation of (p `leftrightarrow` q).

Answer 1

∼ (p `leftrightarrow` q) = ∼ [(p `rightarrow` q) ∧ (q `rightarrow` p)]

= ∼ [(∼ p ∨ q) ∧ (∼ q ∨ p)]

= ∼ (∼ p ∨ q) ∨ ∼ (∼ q ∨ p)

= (p ∧ ∼ q) ∨ (q ∧ ∼ p)