已知2x+y=4,xy=3,求x平方y+1/2xy平方的值

问题描述:

已知2x+y=4,xy=3,求x平方y+1/2xy平方的值

x²y+1/2xy²=(2x+y)xy/2=6

x^2y+xy/2
=xy(2x+y)/2
=3*4/2
=6.

原式=1/2xy(2x+y)
=1/2×3×4
=6