首明握先x3-y3=(x-y)(x2+xy+y2) 其次 x3-y3-3xy=1所以 x3-y3=1+3xy=(x-y)(x2+xy+y2)x-y = (1+3xy)/歼槐(x2+xy+y2) =(1+3xy)/[(x-y)2+3xy]设x-y=A则上式可化为氏槐友 A=(1+3xy)/[A2+3xy] 1+3xy=A3+A*3xy 所以 A=1