Solve a^2 + b^2 = c^3: Integer Solutions

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Discussion Overview

The discussion revolves around finding integer solutions to the equation a2 + b2 = c3, where a, b, and c are distinct integers. Participants explore various approaches, conditions, and examples related to this equation, including constraints on the values of a, b, and c.

Discussion Character

  • Exploratory
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • Some participants propose trivial solutions such as a = -1, b = 0, c = 1, and suggest variations like a = -5, b = 10, c = 5.
  • Others emphasize the need for a condition where a, b, and c are positive integers and distinct from each other.
  • One participant mentions a specific case where a = x3, b = 0, c = x2 as a potential solution.
  • Another participant shares results from a C++ program that found pairs (11, 2, 5) and (18, 26, 10) as solutions for values of a, b, and c up to 30.
  • There is a discussion about primes congruent to 1 mod 4 being expressible as the sum of two squares, and how this relates to the original equation.
  • One participant suggests a method involving Pythagorean triplets to derive solutions by manipulating the equation.
  • Another proposes a method of multiplying both sides of the equation by z4 to find corresponding solutions.

Areas of Agreement / Disagreement

Participants express various viewpoints and methods for approaching the problem, with no consensus on a definitive solution or method. Multiple competing ideas and approaches remain under discussion.

Contextual Notes

Some claims rely on specific mathematical properties or assumptions that may not be universally accepted, and the discussion includes various conditions and constraints that affect the proposed solutions.

frax
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a^2 + b^2 = c^3
(a,b,c - integers, different from each other)
Is there a solution to this?
 
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A trivial solution would be:

a = -1
b = 0
c = 1
 
Zurtex said:
A trivial solution would be:

a = -1
b = 0
c = 1
Of course, for a,b,c you can have:
-5, 10, 5
-17, 68, 17
... and so on.
But let's add a condition |a|<>|b|<>|c|, or just
a, b, c - positive integers, different from each other.
Is there a solution, any idea?
 
There's also
a=x^3,b=0,c=x^2
 
frax said:
Of course, for a,b,c you can have:
-5, 10, 5
-17, 68, 17
... and so on.
But let's add a condition |a|<>|b|<>|c|, or just
a, b, c - positive integers, different from each other.
Is there a solution, any idea?

I wrote a program in C++ for this and got the following results for
a,b,c upto 30

11, 2, 5
18, 26, 10

Of course u can put - signs for a and b.
 
For any prime congruent to 1 mod 4, it is the sum of two squares. For that matter so is the product of two such cases:

(a^2+b^2)(c^2+d^2) = (ac=+/-bd)^2+(ad-/+bc)^2.

This then can be carried to any degree. For example: 5=2^2+1^2 and fits the bill. We have:

5^3=5^2+10^2, and better: 2^2+11^2.
 
:smile: :smile: :smile:
 
Let there be a pythagorian triplet x^2 + y^2 = z^2. Now multiply both sides with z^4,
x^2*z^4 + y^2*z^4 = (xz^2)^2 + yz^2)^2 = z^6 = (z^2)^3.
Find individual pythagorian triplets and you will find corresponding solutions by this method.
 
Let x^2 + y^2 = z. Now multiply both sides with z^2,
x^2*z^2 + y^2*z^2 = xz^2 + yz^2 = z^3
 

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