Questions about the world of GMAT Math from other sources and general math related questions.
kimd6746
 
 

Number Properties: how can n not be an integer if n^2 is?

by kimd6746 Sun Jul 06, 2008 2:46 am

Hello,

I have a question regarding squaring. I know that if the square root of any number always produces an integer, then that number must have been an integer to begin with. However, according to the OG answer explanations, n may or may not be an integer if n^2 is an integer. How can this be?


If √n is an integer, then n must be an integer as well. (understood)

If n^2 is an integer, n may or may not be an integer. (can someone show me/give me an example how n can be an integer or not an integer if n^2 produces an integer?)

Thanks,
guest
 
 

n^2 is an interger...

by guest Mon Jul 07, 2008 1:12 pm

Here's an example and counter example.

(1) n=2, n^2 =4, both are integers.

(2) n=sqrt(2), n^2 =2, n is not an integer
kimd6746
 
 

Number Properties: how can n not be an integer if n^2 is?

by kimd6746 Thu Jul 10, 2008 7:59 pm

OMG! How could I have not recognized this!!!! :oops: Thank you for your example!
Guest
 
 

by Guest Thu Jul 10, 2008 9:26 pm

It only gets worse from here. lol
rfernandez
Course Students
 
Posts: 381
Joined: Fri Apr 07, 2006 8:25 am
 

by rfernandez Fri Jul 18, 2008 12:43 pm

Well done!