A:有最小值2,最大值3
B:有最小值2,无最大值
C:有最大值3,无最小值
D:既无最小值,也无最大值
已知a2+b2=1,b2+c2=2,c2+a2=2,则ab+bc+ca的最小值为( )
—Your T-shirt is nice. It must be expensive.
—Not at all. I only spend $10 it.