Show that there are no positive integers n for which $n^4 + 2n^3 + 2n^2 + 2n + 1$ is a perfect
square. Are there any positive integers $n$ for which $n^4 + n^3 + n^2 + n + 1$ is a perfect square?
If so, find all such $n$.
Pving parameters of perfect cubes and squares
Last edited by Masum on Sat Jul 16, 2011 11:02 pm, edited 1 time in total.
Reason: You can very easily use LaTeX
Reason: You can very easily use LaTeX
Re: Pving parameters of perfect cubes and squares
Hint:
"Inspiration is needed in geometry, just as much as in poetry." -- Aleksandr Pushkin
Please install LaTeX fonts in your PC for better looking equations,
learn how to write equations, and don't forget to read Forum Guide and Rules.
Please install LaTeX fonts in your PC for better looking equations,
learn how to write equations, and don't forget to read Forum Guide and Rules.
- Tahmid Hasan
- Posts:665
- Joined:Thu Dec 09, 2010 5:34 pm
- Location:Khulna,Bangladesh.
Re: Pving parameters of perfect cubes and squares
1.$n^4<n^4 + 2n^3+2n^2+2n+1<(n+1)^4$
the second problem can be solved in the same way.
the second problem can be solved in the same way.
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Re: Pving parameters of perfect cubes and squares
There can be perfect squares between two consecutive fourth powers, e.g. $1^4<2^2<2^4$.Tahmid Hasan wrote:1.$n^4<n^4 + 2n^3+2n^2+2n+1<(n+1)^4$
the second problem can be solved in the same way.
"Everything should be made as simple as possible, but not simpler." - Albert Einstein
- Tahmid Hasan
- Posts:665
- Joined:Thu Dec 09, 2010 5:34 pm
- Location:Khulna,Bangladesh.
Re: Pving parameters of perfect cubes and squares
sorry for my miscalculation ,here's the right one
$(n^2+n)^2<n^4+2n^3+2n^2+2n+1<(n^2+n+1)^2$
$(n^2+n)^2<n^4+2n^3+2n^2+2n+1<(n^2+n+1)^2$
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