已知x+y=2 xy=1\2求x^3y-2x^2y^2+xy^3

已知x+y=2 xy=1\2求x^3y-2x^2y^2+xy^3
已知x+y=2 xy=1\2求x^3y-2x^2y^2+xy^3

已知x+y=2 xy=1\2求x^3y-2x^2y^2+xy^3
(x-y)²
=x²+y²-2xy
=(x+y)²-4xy
=2²-2
=2
所以：
x^3y-2x^2y^2+xy^3
=xy(x²-2xy+y²)
=xy(x-y)²
=(1/2)•2
=1

x??y-2x??Y??+xy??=xy(x??-2xy+y??)=xy(x-y)??x+y=1，xy=3/16(x-y)??=1-3/4=1/4故原式=3/16×﹙1/4﹚=3/64