已知a+b=2,ab=3,求2分之1a^3b+a^2b^2+2分之1ab^3
问题描述:
已知a+b=2,ab=3,求2分之1a^3b+a^2b^2+2分之1ab^3
答
(1/2)a^3b+a^2b^2+(1/2)ab^3
=1/2ab(a^2+2ab+b^2)
=1/2ab(a+b)^2
=1/2×3×2^2
=6