Find all School-related info fast with the new School-Specific MBA Forum

 It is currently 27 Sep 2016, 07:56

### 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

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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# If n is an integer and x^(n) x^(-n) = 0, what is the value

Author Message
Manager
Joined: 26 Jun 2007
Posts: 104
Followers: 2

Kudos [?]: 48 [2] , given: 0

If n is an integer and x^(n) x^(-n) = 0, what is the value [#permalink]

### Show Tags

15 Mar 2008, 00:31
2
KUDOS
This topic is locked. If you want to discuss this question please re-post it in the respective forum.

If n is an integer and x^(n) – x^(-n) = 0, what is the value of x ?
(1) x is an integer.
(2) n ≠ 0

Pls Explain
CEO
Joined: 17 Nov 2007
Posts: 3589
Concentration: Entrepreneurship, Other
Schools: Chicago (Booth) - Class of 2011
GMAT 1: 750 Q50 V40
Followers: 511

Kudos [?]: 3203 [0], given: 360

### Show Tags

15 Mar 2008, 00:43
B

1. x is an integer: $$5^{0} - 5^{-0} = 0$$ and $$7^0 - 7^{-0} = 0$$. insuff.

2. n ≠ 0: we have to consider two possibilities: x=1 and x=0.

x=1: $$1^n - 1^{-n} = 0$$ works perfect.
x=0: $$0^n - 0^{-n} = 0$$ does not work because $$0^{-n}$$ is undefined for n>0 as well as $$0^{n}$$ is undefined for n<0.
Therefore, x=1.
_________________

HOT! GMAT TOOLKIT 2 (iOS) / GMAT TOOLKIT (Android) - The OFFICIAL GMAT CLUB PREP APP, a must-have app especially if you aim at 700+ | PrepGame

Manager
Joined: 26 Jun 2007
Posts: 104
Followers: 2

Kudos [?]: 48 [0], given: 0

### Show Tags

15 Mar 2008, 00:53
walker wrote:
B

1. x is an integer: and . insuff.

2. n ≠ 0: we have to consider two possibilities: x=1 and x=0.

x=1: works perfect.
x=0: does not work because is undefined for n>0 as well as is undefined for n<0.
Therefore, x=1.
thats what i thought - B is not the OA im afraid
CEO
Joined: 17 Nov 2007
Posts: 3589
Concentration: Entrepreneurship, Other
Schools: Chicago (Booth) - Class of 2011
GMAT 1: 750 Q50 V40
Followers: 511

Kudos [?]: 3203 [0], given: 360

### Show Tags

15 Mar 2008, 00:56
Excellent question!!! +2

x=-1 works for even n. Therefore, E
_________________

HOT! GMAT TOOLKIT 2 (iOS) / GMAT TOOLKIT (Android) - The OFFICIAL GMAT CLUB PREP APP, a must-have app especially if you aim at 700+ | PrepGame

Manager
Joined: 26 Jun 2007
Posts: 104
Followers: 2

Kudos [?]: 48 [0], given: 0

### Show Tags

20 Mar 2008, 11:38

OA = E
tnx
Re: GmatSet29 Q3   [#permalink] 20 Mar 2008, 11:38
Display posts from previous: Sort by