先化简,再求值[x(x^2y^2-xy)-y(x^2+x^3y)]/3x,其中x=1,y=-1/2
问题描述:
先化简,再求值[x(x^2y^2-xy)-y(x^2+x^3y)]/3x,其中x=1,y=-1/2
答
[x(x^2y^2-xy)-y(x^2+x^3y)]/3x=[x^3y^2-x^2y-x^2y-x^3y^2]/3x=-2x^2y/3x
=(-2/3)xy=(-2/3)*1*(-1/2)=1/3