Give interpretations to prove that each of the following wffs is not valid: (thereexists x) A(x) lambda (thereexists x) B(x) rightarrow (thereexists.x)[A(x) lambda B(x)] (forall x)(thereexists y)P(x, y) rightarrow (therexists x)(forall y)P(x, y) (forall x)[P(x) rightarrow Q(x)] rightarrow [(thereexists x)P(x) rightarrow (forall x)Q(x)] (forall x)[A(x)]' doubleheadarrow [(forall x) A(x)]