(x^+1)(x^4+1)(x^8+1)(x^-1)/x^7=(x^16+1)/x^7
通分,反复用平方差公式
(x+1/x)(x^2+1/x^2)(x^4+1/x^4)(x^2-1)
=(x-1/x)(x+1/x)(x^2+1/x^2)(x^4+1/x^4)(x^2-1)/(x-1/x)
=(x^2-1/x^2)(x^2+1/x^2)(x^4+1/x^4)(x^2-1)/(x-1/x)
=(x^4-1/x^4)(x^4+1/x^4)(x^2-1)/[(x^2-1)/x]
=(x^8-1/x^8)x
=x^9-1/x^7
(x^8-1/x^8)