MHB Square Number Pairs from 1-50: Counting Rules

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The discussion focuses on finding pairs of integers from 1 to 50 where at least one number is a square and their sum is also a square. The equation $x^2 + y = z^2$ is central to determining valid pairs, leading to the factorization $y = (z - x)(z + x)$. A correction was made regarding the sign in the equation, clarifying that $y$ should be expressed as $y = z^2 - x^2$. The method involves factoring $y$ into two integers, which helps derive formulas for $x$ and $z$. The thread emphasizes the importance of accurately applying these mathematical principles to count valid pairs.
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Two integers will be taken from 1 to 50, where at least one of them should be a square number and sum of them should also be a square number. How many different pair like this can be found? Will I count (9,16) and (16,9) as one ?
 
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So $x^2+ y= z^2$ for x, y, and z integers. That is the same as $x^2- z^2= (x- z)(x+ z)= y$. Look at the ways to factor y: y= mn and the x- z= m, x+ z= n. Adding those two equations, 2x= m+ n, x= (m+ n)/2. Subtracting, 2z= n- m, z= (n- m)/2.

added much later: I've noticed that I have a sign error: from $x^2+ y= z^2$, $y= z^2- x^2$, not $x^2- x^2$. So y= (z- x)(z+ x). Taking y= mn, z- x= m, z+ x= n so that 2z= n+m, z= (n+m)/2, 2x= n- m so x= (n-m)/2, just the opposite of what I had before.
 
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