根据:a²-b²=(a+b)(a-b)
(x²+y²)²-(2xy)²
假设:(x²+y²)²=a²,(2xy)²=b²
a²-b²=(x²+y²)²-(2xy)²=(x²+y²+2xy)(x²+y²-2xy)(经过整理得)
=(x²+2xy+y²)(x²-2xy+y²)
根据:a²-b²=(a+b)(a-b)
(x²+y²)²-(2xy)²
假设:(x²+y²)²=a²,(2xy)²=b²
a²-b²=(x²+y²)²-(2xy)²=(x²+y²+2xy)(x²+y²-2xy)(经过整理得)
=(x²+2xy+y²)(x²-2xy+y²)