Is 3 a Common Divisor for p and q When 3p² = q²?

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Homework Help Overview

The discussion revolves around the mathematical relationship defined by the equation 3p² = q², where p and q are integers. Participants are exploring whether 3 is a common divisor of both p and q based on this equation.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • Some participants attempt to analyze the implications of the equation, particularly focusing on the divisibility of q by 3 and questioning how this relates to p. Others raise points about the nature of square roots and their relevance to the problem.

Discussion Status

The discussion is ongoing, with various lines of reasoning being explored. Some participants have provided insights and suggestions for rewriting the equation to further investigate the properties of p and q. However, there is no explicit consensus on the conclusions drawn from these discussions.

Contextual Notes

Participants note the importance of p and q being integers, which influences the nature of the arguments being made regarding divisibility and the properties of square roots.

lordy12
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If 3p^2 = q^2 and p and q are integers, how do I prove that 3 is a common divisor for p and q?
My attempt: q^2 is divisible by 3, so q is divisible by 3. I can't prove that p is divisible by 3.
 
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Any integer that is not a perfect square has an irrational square root. What can you do with that?
 
Werg22 said:
Any integer that is not a perfect square has an irrational square root. What can you do with that?

Personally, I have no idea what you can do with that.
 
lordy12 said:
If 3p^2 = q^2 and p and q are integers, how do I prove that 3 is a common divisor for p and q?
My attempt: q^2 is divisible by 3, so q is divisible by 3. I can't prove that p is divisible by 3.

Now, just re-write it as p^2 = q^2/3. What does that tell you about p?

Remember, p is an integer so p^2 is also an integer. And q is divisible by 3, but there is only one 3. :wink:

Finish it off from there.
 
Lol, yeah maybe it's not very relevant. Let me repent:

A power has the same prime factors than its root.
 
3|q, rewrite q=3q'
 
oops...I completely disregarded the fact that p and q are integers.

sorry
 

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