题目4.用等值演算法证明下列等值式.-|||-(1) Leftrightarrow (plambda q)V(plambda -q)-|||-(2) ((parrow q)(Aarrow r)arrow Leftrightarrow (parrow (qAr))-|||-③ -(p-q)leftharpoons (pvq)lambda -(phq)-|||-④(p^-q)V (-p^q)=(pVq)^-(p^q)题目解答答案