Proof - If the square of an integer is even,. .

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Homework Help Overview

The discussion revolves around a proof related to the properties of integers, specifically addressing the statement: "If the square of an integer is even, then the integer itself is even." Participants are exploring different approaches to prove this statement and clarifying definitions related to even and odd integers.

Discussion Character

  • Exploratory, Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants discuss the possibility of proving the statement directly and consider the converse of the original claim. There are questions about definitions of prime numbers and whether proof by contradiction is applicable in this context. Some participants suggest proving that if an integer is odd, then its square is odd as a potential approach.

Discussion Status

The discussion is ongoing, with participants sharing their thoughts on different proof strategies and definitions. There is no explicit consensus yet, but various lines of reasoning are being explored, including direct proof and proof by contradiction.

Contextual Notes

Some participants express uncertainty about the definitions they are using and whether their approaches align with the requirements of the proof. There is also mention of a lack of similar examples in available resources.

yanjt
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Hi,
I have no idea on how to start to do this question.
If the square of an integer is even,then the integer itself is even

I try to check some books but i can't get any similar examples.I wonder if I can directly prove the n=2k, n^2 = 2(2k^2).

Thanks!
 
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But that is the converse of what you were asked to show. You want to show that if m^2 is even, then m is even. One of the definitions of a prime number makes this instantaneous. What definitions of prime do you know?

Alternatively you can show that if n is odd, then n^2 is odd.
 
Welcome to PF!

yanjt said:
Hi,
I have no idea on how to start to do this question.
If the square of an integer is even,then the integer itself is even

I try to check some books but i can't get any similar examples.I wonder if I can directly prove the n=2k, n^2 = 2(2k^2).

Thanks!

Hi yanjt! Welcome to PF! :smile:

Try proving it the other way round:

if an integer is odd, its square is odd. :wink:
 


Prime number is number that can be divided by or itself.
if i prove that an integer is odd,its square is odd,I am not using contradiction to prove it,right?I can show that if an integer is odd,its square is odd.Yet, how can i show that if the square of an integer is even,the integer itself is even?

Thanks for ur help!

p/s:Thanks tiny-tim!I found this website is really useful!=)
 


What's wrong with using proof by contradiction?
 


Nothing is wrong using contradiction.What i mean is that,i wonder if proof "if n is odd,n^2 is odd" is a kind of contradiction?
 

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