(x-y)(x+y)(x²+y²)(x四次方+y四次方)
问题描述：
(x-y)(x+y)(x²+y²)(x四次方+y四次方)
答
(x-y)(x+y)(x²+y²)(x⁴+y⁴)
=(x²-y²)(x²+y²)(x⁴+y⁴)
=(x⁴-y⁴)(x⁴+y⁴)
=x^8 -y^8
x^8表示x的8次方.
提示：就是反复利用平方差公式.