prep里的数学题....

ayumissing · 发表于 2010-8-30 15:33:59

DS: If ab≠0 and point (-a,b) and (-b,a) are in the same quadrant of the xy-plane, is point (-x,y) in this quadrant?
1. xy＞0
2. ax＞0
这题没看明白什么意思

ayumissing · 发表于 2010-8-30 16:39:55

没人啊............偶明天就考啦......

Leliolevine · 发表于 2010-8-30 16:55:07

(-a,b)和(-b,a)在同一象限，则-b,-a同号，b,a同号，得出ab>0 (-x,y)在同一象限需要满足xa>0 yb>0 所以仅仅是一个条件是不能推出的。选C （ xy>0 ax>0 则xa>0 yb>0）

DS: If ab≠0 and point (-a,b) and (-b,a) are in the same quadrant of the xy-plane, is point (-x,y) in this quadrant?
1. xy＞0
2. ax＞0
这题没看明白什么意思

-- by 会员 ayumissing (2010/8/30 15:33:59)

所属分类: GMAT考试