— ______ do you get up in the morning?
—At six.
A:Where
B:What time
C:How
△ABC的内角A,B,C的对边分别为a,b,c,若a,b,c成等比数列,且c=2a,则cosB=( )
设a,b,C为正数,
求证: a2+b2+b2+c2+a2+c2≥2a+b+c .