Last visit was: 25 Apr 2024, 08:32 It is currently 25 Apr 2024, 08:32

Close
GMAT Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Close
Request Expert Reply
Confirm Cancel
SORT BY:
Date
User avatar
Intern
Intern
Joined: 06 Apr 2010
Posts: 48
Own Kudos [?]: 104 [2]
Given Kudos: 2
Send PM
avatar
Manager
Manager
Joined: 10 Jan 2010
Posts: 137
Own Kudos [?]: 25 [0]
Given Kudos: 67
Schools:Tuck 2013
WE 1: Big 4
Send PM
avatar
Intern
Intern
Joined: 21 Mar 2010
Posts: 8
Own Kudos [?]: 4 [1]
Given Kudos: 0
Send PM
User avatar
Intern
Intern
Joined: 06 Apr 2010
Posts: 48
Own Kudos [?]: 104 [0]
Given Kudos: 2
Send PM
Re: What is X? [#permalink]
1) X^X=|X|
What about x=0?
0^0=|0|
so the statement should be true for x=0 and 1. Am I wrong?
Math Expert
Joined: 02 Sep 2009
Posts: 92914
Own Kudos [?]: 618955 [1]
Given Kudos: 81595
Send PM
Re: What is X? [#permalink]
1
Bookmarks
Expert Reply
Eden wrote:
What is integer X?
(1) X^X=|X|
(2) X^2=|X^3|

Answer is but I'm not so sure..


Eden wrote:
1) X^X=|X|
What about x=0?
0^0=|0|
so the statement should be true for x=0 and 1. Am I wrong?


0^0, in some sources equals to 1, some mathematicians say it's undefined. Note that the case of 0^0 is not tested on the GMAT. (But anyway \(0^0\neq{0}\))

Given: \(x=integer\). Q: \(x=?\)

(1) \(x^x=|x|\) --> \(x=1\). Sufficient.
(2) \(x^2=|x^3|\) --> \(x=1\) or \(x=-1\) or \(x=0\). Not sufficient.

Answer: A.

Hope it helps.
Math Expert
Joined: 02 Sep 2009
Posts: 92914
Own Kudos [?]: 618955 [0]
Given Kudos: 81595
Send PM
Re: What is X? [#permalink]
Expert Reply
sid4674 wrote:
What is integer X?
(1) X^X=|X|
(2) X^2=|X^3|

For 1) x^x=|x|

X =1, 1*1=|1|=>1=1
X=-1, -1*-1=|-1|=>1=1

hence A is not sufficient, could anyone please explain how statement one alone is sufficient.


Your calculation is not correct.

Statement (1) is: \(x^x=|x|\), so if \(x=-1\), then \((-1)^{-1}=\frac{1}{(-1)^1}=\frac{1}{-1}=-1\neq|-1|=1\).
User avatar
VP
VP
Joined: 06 Sep 2013
Posts: 1345
Own Kudos [?]: 2391 [0]
Given Kudos: 355
Concentration: Finance
Send PM
Re: What is integer x? [#permalink]
Is it valid if for statement 2 we divide both sides by x^2, hence obtaining

x = abs (x)

Therefore any >=0 number will do

Thanks
Cheers
J
User avatar
Non-Human User
Joined: 09 Sep 2013
Posts: 32675
Own Kudos [?]: 821 [0]
Given Kudos: 0
Send PM
Re: What is integer x? [#permalink]
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
GMAT Club Bot
Re: What is integer x? [#permalink]
Moderator:
Math Expert
92914 posts

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne