已知a-b=-2,ab=-2,则1/2a^3b-a^2b^2+1/2ab^3的值是

问题描述:

已知a-b=-2,ab=-2,则1/2a^3b-a^2b^2+1/2ab^3的值是

1/2a^3b-a^2b^2+1/2ab^3
=1/2ab(a²-2ab+b²)
=1/2ab(a-b)²
=1/2×(-2)×(-2)²
=-4