Can Anyone Help Crack the Nut on Solving (m,n) Pairs for this Equality?

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In summary, the conversation was about finding pairs of nonnegative integers $(m,n)$ that satisfy the equality $(m-n)^2(n^2-m) = 4m^2n$. The participants discussed various strategies and potential solutions, such as taking the equation modulo 2 and eliminating odd numbers, trying solutions with $m=2n$ and $m=3n$, and using clever algebraic manipulations. In the end, the solution of $(m,n)=(36,18)$ was found, with additional solutions of $(36,12)$ and potentially others.
  • #1
lfdahl
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Find the pairs of nonnegative integers, $(m,n)$, which obey the equality:

\[(m-n)^2(n^2-m) = 4m^2n\]

So far, I haven´t found a single pair, but I cannot prove, that the set of solutions is empty.
Perhaps, someone can help me to crack this nut?
 
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  • #2
lfdahl said:
Find the pairs of nonnegative integers, $(m,n)$, which obey the equality:

\[(m-n)^2(n^2-m) = 4m^2n\]

So far, I haven´t found a single pair, but I cannot prove, that the set of solutions is empty.
Perhaps, someone can help me to crack this nut?
My suggestion is to take the whole thing a modulo 2 so you would have only a limited number of cases to check.

-Dan
 
  • #3
Ah well. It was a nice idea, but it doesn't actually help a whole lot. Good luck with it and if I get any other wild ideas I'll let you know. :)

-Dan
 
  • #4
lfdahl said:
Find the pairs of nonnegative integers, $(m,n)$, which obey the equality:

\[(m-n)^2(n^2-m) = 4m^2n\]
Not a solution but some elimination

So far, I haven´t found a single pair, but I cannot prove, that the set of solutions is empty.
Perhaps, someone can help me to crack this nut?

first neither can be odd
because if both are odd LHs is divisible by 8 being product of 3 even numbers and RHS is not

if one is odd then LHS is odd and RHS even.

thus both are even
you can have this as a starting point
 
  • #5
lfdahl said:
Find the pairs of nonnegative integers, $(m,n)$, which obey the equality:

\[(m-n)^2(n^2-m) = 4m^2n\]

So far, I haven´t found a single pair, but I cannot prove, that the set of solutions is empty.
Perhaps, someone can help me to crack this nut?
Try for a solution with $m=2n$: $$(2n-n)^2(n^2-2n) = 16n^3,$$ $$n^3(n-2) = 16n^3,$$ $$ n-2 = 16,$$ $$ n=18.$$ That gives the solution $(m,n) = (36,18).$

Edit. You can also try $m=3n$, which leads to the solution $(36,12).$
 
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  • #6
Clever Opalg! That generalizes nicely. (Bow)

-Dan
 
  • #7
Thankyou so much, Opalg, kaliprasad for your help to "crack the nut".
Thankyou, topsquark for nice and helpful comments.
 

1. What is the purpose of finding pairs of integers (m,n)?

The purpose of finding pairs of integers (m,n) is to identify two numbers that satisfy a specific relationship or equation. This can be useful in various mathematical and scientific applications, such as solving equations, graphing functions, and analyzing data.

2. How do you find pairs of integers (m,n)?

To find pairs of integers (m,n), you can use algebraic methods, such as substitution or elimination, to solve an equation or system of equations. You can also use visual methods, such as graphing, to identify points where the coordinates are both integers.

3. Can there be more than one pair of integers (m,n) that satisfy a given equation?

Yes, there can be multiple pairs of integers (m,n) that satisfy a given equation. For example, the equation y = 2x has an infinite number of solutions, where x and y are both integers.

4. Are there any special types of pairs of integers (m,n) that have specific properties or applications?

Yes, there are several types of pairs of integers (m,n) that have specific properties or applications. Some examples include prime numbers, perfect squares, and Pythagorean triples, which have been studied extensively in number theory and have practical applications in cryptography and computer science.

5. How are pairs of integers (m,n) used in real-world situations?

Pairs of integers (m,n) are used in a wide range of real-world situations, from calculating distances and areas in geometry to predicting patterns and relationships in data. They are also commonly used in coding and programming to represent coordinates and indices in arrays and matrices.

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