因为(4x-2y-1)^2+(xy-2)^(1/2)=0
所以(4x-2y-1)^2=0,(xy-2)^(1/2)=0
解得：xy=2,2x-y=1/2
由上列各式得：4x^2-4xy+y^2=4x^2-4*2+y^2=1/4
得：4x^2+y^2=33/4
所以4x^2y-4x^2y^2+xy^3
=4(xy)x^2-4(xy)^2+(xy)y^2
=4*2x^2-4*2^2+2y^2
=2(4x^2+y^2)-16
=2*33/4-16=1/2