已知x+y=2,xy=1/2,求x3y-2x2y2+xy3的值.
问题描述:
已知x+y=2,xy=
,求x3y-2x2y2+xy3的值. 1 2
答
原式=xy(x2-2xy+y2)
=xy[(x+y)2-4xy]
=
(22−4×1 2
)1 2
=1.