This is a derivation using symbolic logic from philosophy, i am stuck deriving (A <-> B )this is assumption into ((A & B ) v ~(A v B )) this is goal? the ~ is a negation and v a disjunction, <-> is a biconditional, and & is the conjunction. We can use all basic derivation rules, for introduction and elimination of the conjunction, disjunction, negation, conditional, biconditional, and falsum.