若n=2m
f(x)=(x^(8m+4)-1)/(x^4-1)
=(x^(4m+2)-1)(x^(4m+2)+1)/(x^4-1)
=(1+x^2+x^4+...+x^4m)(x^(4m+2)+1)/(x^2+1)
=g(x)*[(x^2)^(2m+1)+1]/(x^2+1),而x^2+1整除[(x^2)^(2m+1)+1],所以g(x)整除f(x).
反过来,一个反例即可：n=1时g(x)=1+x^2,f(x)=1+x^4,g(x)不整除f(x).
证毕.