已知:x-y=1,求证:x3-3xy-y3=

已知:x-y=1,求证:x3-3xy-y3=1
2024-11-25 01:33:43
推荐回答(1个)
回答1:

证明:
x3-3xy-y3
=x3-y3-3xy
=(者虚x-y)厅嫌猜(x2+xy+y2)-3xy
=x2+xy+y2-3xy
=x2-2xy+y2
=(扮型x-y)2
=1