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

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In summary, a solution to the equation a^2 + b^2 = c^3 can be found by using pythagorean triplets and multiplying both sides of the equation with appropriate terms. The condition of integers a, b, c being different from each other can be fulfilled by using positive integers and adding the condition |a| <> |b| <> |c|.
  • #1
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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  • #2
A trivial solution would be:

a = -1
b = 0
c = 1
 
  • #3
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?
 
  • #4
There's also
a=x^3,b=0,c=x^2
 
  • #5
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.
 
  • #6
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.
 
  • #7
:smile: :smile: :smile:
 
  • #8
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.
 
  • #9
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
 

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

What is the Pythagorean Triple formula?

The Pythagorean Triple formula states that in a right triangle, the square of the length of the hypotenuse is equal to the sum of the squares of the lengths of the other two sides. In other words, a^2 + b^2 = c^2.

Can the equation a^2 + b^2 = c^3 have integer solutions?

Yes, the equation can have integer solutions. These solutions are known as Pythagorean Triples, where a, b, and c are positive integers and a^2 + b^2 = c^3. Some examples include (3, 4, 5) and (5, 12, 13).

Are there an infinite number of solutions to the equation a^2 + b^2 = c^3?

Yes, there are an infinite number of solutions to this equation. This is because there are an infinite number of Pythagorean Triples that satisfy the equation.

How do you find integer solutions to the equation a^2 + b^2 = c^3?

One way to find integer solutions is by using the Euclidean formula, which states that a = 2mn, b = m^2 - n^2, and c = m^2 + n^2, where m and n are positive integers. This formula will generate Pythagorean Triples that satisfy the equation.

Are there any other methods for solving the equation a^2 + b^2 = c^3?

Yes, there are other methods such as using modular arithmetic and Diophantine equations. However, these methods can be more complex and may require advanced mathematical knowledge.

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