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

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If n is an integer and x^(n) x^(-n) = 0, what is the value [#permalink] New post 14 Mar 2008, 23:31
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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
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CEO
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Concentration: Entrepreneurship, Other
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Re: GmatSet29 Q3 [#permalink] New post 14 Mar 2008, 23:43
Expert's post
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.
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Manager
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Re: GmatSet29 Q3 [#permalink] New post 14 Mar 2008, 23:53
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
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Concentration: Entrepreneurship, Other
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Re: GmatSet29 Q3 [#permalink] New post 14 Mar 2008, 23:56
Expert's post
Excellent question!!! +2

x=-1 works for even n. Therefore, E
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Re: GmatSet29 Q3 [#permalink] New post 20 Mar 2008, 10:38
sorry for the late reply

OA = E
tnx
Re: GmatSet29 Q3   [#permalink] 20 Mar 2008, 10:38
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If n is an integer and x^(n) x^(-n) = 0, what is the value

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