[证明题,7.1分]
在个体域D={a1,a2,…，an}中证明等价式：

证明：( x)(A(x)→B(x)) x(┐A(x)∨B(x)) (┐A(a1)∨B(a1))∨(┐A(a2)∨B(a2))∨…∨(┐A(an)∨B(an))) (┐A(a1)∨A(a2)∨…∨┐A(an)∨(B(a1)∨B(a2)∨…∨(B(an)) ┐(A(a1)∧A(a2)∧…∧A(an))∨(┐B(a1)∨B(a2)∨…∨(B(an)) ┐( x)A(x)∨( x)B(x) ( x)A(x)→( x)B(x)