已知x+y=1,求1/2x²+xy+1/2y²的值
问题描述:
已知x+y=1,求1/2x²+xy+1/2y²的值
答
低估好
1/2x²+xy+1/2y²
=1/2(x²+2xy+y²)
=1/2(x+y)²
=1/2*1²
=1/2