Integers

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Integers

by salma » Sat Dec 08, 2007 1:17 pm
Is n an integer?
(1) n^2 is an integer
(2) square root of n is an integer
The answers says that from (2) we can know that n is an integer but not from (1). I cannot think of a non integer which square root is an integer?

Am I missing stg?

Thx

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Re: Integers

by jayhawk2001 » Sat Dec 08, 2007 4:38 pm
[quote="salma"]Is n an integer?
(1) n^2 is an integer
(2) square root of n is an integer
The answers says that from (2) we can know that n is an integer but not from (1). I cannot think of a non integer which square root is an integer?
Thx[/quote]

1 - insufficient. Knowing n^2 is an integer does not tell us anything
about n. N could be 2, n could be sqrt(2). Both will yield integers for n^2

2 - sufficient. If sqrt(n) is an integer, then n is definitely an integer.

Hope this helps

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Re: Integers

by hemanth28 » Sat Dec 08, 2007 11:25 pm
salma wrote:Is n an integer?
(1) n^2 is an integer
(2) square root of n is an integer
The answers says that from (2) we can know that n is an integer but not from (1). I cannot think of a non integer which square root is an integer?

Am I missing stg?

Thx
That is exactly the reason why answer is (B)