(x-y)^m/(y-x)^n=x-y,
(x-y)^m/[(-1)^n(x-y)^n]=x-y,
(x-y)^(m-n)=(-1)^n(x-y),
当n=2,4,6,8,...,及m-n=1,时等式成立,
所以,m=n+1,n=2,4,6,8,...
(x-y)^m/(y-x)^n=x-y,
(x-y)^m/[(-1)^n(x-y)^n]=x-y,
(x-y)^(m-n)=(-1)^n(x-y),
当n=2,4,6,8,...,及m-n=1,时等式成立,
所以,m=n+1,n=2,4,6,8,...