positive/negative

This topic has expert replies
User avatar
Legendary Member
Posts: 659
Joined: Mon Dec 14, 2009 8:12 am
Thanked: 32 times
Followed by:3 members

positive/negative

by Gurpinder » Fri Sep 17, 2010 11:33 am
Image

doesent (1) mean y= +.

thx.
"Do not confuse motion and progress. A rocking horse keeps moving but does not make any progress."
- Alfred A. Montapert, Philosopher.

User avatar
Master | Next Rank: 500 Posts
Posts: 164
Joined: Sun Jul 18, 2010 5:26 am
Thanked: 49 times
Followed by:4 members
GMAT Score:710

by Maciek » Fri Sep 17, 2010 3:25 pm
Hi!

IMO E

x^2*y > 0 ?
x^2*y > 0 if y > 0 and (x < 0 or x > 0 )

(1) y^2 > 0
Therefore, y < 0 or y > 0
Statement (1) ALONE is INSUFFICIENT
(2) x = 2
Statement (2) ALONE is INSUFFICIENT
Statements (1) & (2) BOTH are together INSUFFICIENT.

Hope it helps!
Best,
Maciek
"There is no greater wealth in a nation than that of being made up of learned citizens." Pope John Paul II

if you have any questions, send me a private message!

should you find this post useful, please click on "thanks" button :)

User avatar
Senior | Next Rank: 100 Posts
Posts: 82
Joined: Sat Aug 21, 2010 8:18 am
Location: India
Thanked: 5 times

by sumit.sinha » Sat Sep 18, 2010 4:26 am
Gurpinder wrote:Image

doesent (1) mean y= +.

thx.
No y^2 >0 does not mean y is +ve.
Consider it this way,
y*y = +ve
so, -ve * -ve = +ve and also +ve * +ve = +ve.
So y can be either -ve or +ve.

User avatar
Legendary Member
Posts: 659
Joined: Mon Dec 14, 2009 8:12 am
Thanked: 32 times
Followed by:3 members

by Gurpinder » Sat Sep 18, 2010 8:29 am
I assumed something silly.

I read somewhere that when a questions asks you whether --> y^2>0, is y positive. all this is asking you is is y>0.

I misapplied this here!

I see why (E) is the right answer.

Just a little doubt, can you guys clarify what the questions means when it says x*y is defined as X^2*y

Thx.
"Do not confuse motion and progress. A rocking horse keeps moving but does not make any progress."
- Alfred A. Montapert, Philosopher.

User avatar
Senior | Next Rank: 100 Posts
Posts: 82
Joined: Sat Aug 21, 2010 8:18 am
Location: India
Thanked: 5 times

by sumit.sinha » Sat Sep 18, 2010 8:52 am
Gurpinder wrote:I assumed something silly.

I read somewhere that when a questions asks you whether --> y^2>0, is y positive. all this is asking you is is y>0.

I misapplied this here!

I see why (E) is the right answer.

Just a little doubt, can you guys clarify what the questions means when it says x*y is defined as X^2*y

Thx.
It is function question.
it says x*y is defined as x^2*y.
i.e. if x=2 and y=3 then 2*3 value will be 2^2*3 = 12 even tough 2*3 (in real world)=6.
Cheers,
Sumit

User avatar
Legendary Member
Posts: 659
Joined: Mon Dec 14, 2009 8:12 am
Thanked: 32 times
Followed by:3 members

by Gurpinder » Sat Sep 18, 2010 9:25 am
sumit.sinha wrote:
Gurpinder wrote:I assumed something silly.

I read somewhere that when a questions asks you whether --> y^2>0, is y positive. all this is asking you is is y>0.

I misapplied this here!

I see why (E) is the right answer.

Just a little doubt, can you guys clarify what the questions means when it says x*y is defined as X^2*y

Thx.
It is function question.
it says x*y is defined as x^2*y.
i.e. if x=2 and y=3 then 2*3 value will be 2^2*3 = 12 even tough 2*3 (in real world)=6.
Oh man. I need some Coffee.

Thx Sumit.
"Do not confuse motion and progress. A rocking horse keeps moving but does not make any progress."
- Alfred A. Montapert, Philosopher.

User avatar
Senior | Next Rank: 100 Posts
Posts: 82
Joined: Sat Aug 21, 2010 8:18 am
Location: India
Thanked: 5 times

by sumit.sinha » Sat Sep 18, 2010 9:38 am
Gurpinder wrote:
sumit.sinha wrote:
Gurpinder wrote:I assumed something silly.

I read somewhere that when a questions asks you whether --> y^2>0, is y positive. all this is asking you is is y>0.

I misapplied this here!

I see why (E) is the right answer.

Just a little doubt, can you guys clarify what the questions means when it says x*y is defined as X^2*y

Thx.
It is function question.
it says x*y is defined as x^2*y.
i.e. if x=2 and y=3 then 2*3 value will be 2^2*3 = 12 even tough 2*3 (in real world)=6.
Oh man. I need some Coffee.

Thx Sumit.
Yeah they look a little awkward first time around.
Hey, why is your target score 900+ :P . i think the exam is out of 800. lol
Cheers,
Sumit

User avatar
Legendary Member
Posts: 659
Joined: Mon Dec 14, 2009 8:12 am
Thanked: 32 times
Followed by:3 members

by Gurpinder » Sat Sep 18, 2010 9:53 am
sumit.sinha wrote:
Gurpinder wrote:
sumit.sinha wrote:
Gurpinder wrote:I assumed something silly.

I read somewhere that when a questions asks you whether --> y^2>0, is y positive. all this is asking you is is y>0.

I misapplied this here!

I see why (E) is the right answer.

Just a little doubt, can you guys clarify what the questions means when it says x*y is defined as X^2*y

Thx.
It is function question.
it says x*y is defined as x^2*y.
i.e. if x=2 and y=3 then 2*3 value will be 2^2*3 = 12 even tough 2*3 (in real world)=6.
Oh man. I need some Coffee.

Thx Sumit.
Yeah they look a little awkward first time around.
Hey, why is your target score 900+ :P . i think the exam is out of 800. lol
lol.... just having fun =)
"Do not confuse motion and progress. A rocking horse keeps moving but does not make any progress."
- Alfred A. Montapert, Philosopher.