(a4-b4)4/((a2+b2)2.(a2-b2)2)

问题描述:

(a4-b4)4/((a2+b2)2.(a2-b2)2)

(a4-b4)^4/((a2+b2)².(a2-b2)²=[(a²+b²)^4*(a²-b²)^4]/(a2+b2)².(a2-b2)²=(a²+b²)²*(a²-b²)²=(a^4-b^4)²=a^8-2a^4b^4+b^8