Does the equation $a^2=b^4+b^2+1$ have integer solutions?

  • Context: MHB 
  • Thread starter Thread starter anemone
  • Start date Start date
  • Tags Tags
    Challenge Integer
Click For Summary

Discussion Overview

The discussion revolves around the equation $a^2=b^4+b^2+1$ and whether it has integer solutions. Participants explore the existence of solutions and the implications of specific values for $a$ and $b$.

Discussion Character

  • Debate/contested

Main Points Raised

  • Some participants assert that the equation does not have integer solutions.
  • Others propose that $(a,\,b)=(\pm1,\,0)$ constitutes valid integer solutions.
  • A participant acknowledges a misunderstanding regarding the solutions and suggests rephrasing the problem to imply that it does not have integer solutions, except for $(a,\,b)=(\pm1,\,0)$.

Areas of Agreement / Disagreement

There is disagreement among participants regarding the existence of integer solutions to the equation. Some claim there are no solutions, while others identify specific solutions.

Contextual Notes

Participants have not reached a consensus on the overall validity of the equation's integer solutions, and there are indications of misunderstandings regarding the problem's framing.

anemone
Gold Member
MHB
POTW Director
Messages
3,851
Reaction score
115
Show that the equation $a^2=b^4+b^2+1$ does not have integer solutions.
 
Mathematics news on Phys.org
anemone said:
Show that the equation $a^2=b^4+b^2+1$ does not have integer solutions.
$a=\pm 1 ,\, and \,\, b=0 $ are two sets of integer solutions
 
Albert said:
$a=\pm 1 ,\, and \,\, b=0 $ are two sets of integer solutions

Oh...it was my bad that I didn't see $(a,\,b)=(\pm1,\,0)$ is the valid solution to this problem. Sorry!:o

Let me rephrase the original problem so that it does not have integer solutions, except for $(a,\,b)=(\pm1,\,0)$.
 
$a^2=b^4+b^2+1---(1)$
$\left | a \right |$ must be odd
let $a=2x+1,\,\, and, \,\, y=b^2\geq 0$
from (1) we have:
$4x^2+4x+1=y^2+y+1$
$\therefore 4x(x+1)=y(y+1)---(2)$
the only possible solutions for (2) will be :$4x(x+1)=y(y+1)=0$
we get $x=0 ,\,\, or,\,\, x=-1$
and the corresponding solutions of $a,\,\, and \,\,\, b $ will be :$a=\pm 1,\,\, and\,\, \, b=0$
 

Similar threads

  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 4 ·
Replies
4
Views
1K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 1 ·
Replies
1
Views
29K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 7 ·
Replies
7
Views
4K
  • · Replies 1 ·
Replies
1
Views
1K