若x+y=1,则1/2x²+xy+1/2y²=
问题描述:
若x+y=1,则1/2x²+xy+1/2y²=
rt.
答
1/2x²+xy+1/2y²=(1/2)(x²+2xy+y²)
=(1/2)(x+y)²
=(1/2)*1²
=1/2