已知2X-Y=1/3,XY=2,求4X^3y-3x^2y^2+xy^3=多少要过程_数学解答

已知2X-Y=1/3,XY=2,求4X^3y-3x^2y^2+xy^3=多少要过程

人气：173 ℃　时间：2020-04-10 12:51:06

解答

2X-Y=1/3
XY=2
4X^3y-3x^2y^2+xy^3
= 4X^3y-4x^2y^2+xy^3 + x^2y^2
= xy (4X^2-4xy+y^2) + x^2y^2
= xy(2x-y)^2 + x^2y^2
= 2 * (1/3)^2 + 2^2
= 2/9 +4
= 38/9