I am being stuck in this question. I was asked to prove that without using truth tables. I was taught how to prove that using truth table.
$(p \iff q) \equiv (p \Rightarrow q)\land(q \Rightarrow p)$
So, my first step is to use conditional identities: $$(p→q)∧(q→p) \equiv (\neg p \lor q) ∧(\neg q \lor p),$$ but I think I can't get any clue to prove that. How should I approach this?