BdMO National Higher Secondary 2015#2

Discussion on Bangladesh Mathematical Olympiad (BdMO) National
samiul_samin
Posts:1007
Joined:Sat Dec 09, 2017 1:32 pm
BdMO National Higher Secondary 2015#2

Unread post by samiul_samin » Thu Feb 21, 2019 1:38 pm

Let $N$ be the number if pairs of integers $(m,n)$ that satisfies the equation $m^2+n^2=m^3$
Is $N$ finite or infinite?If $N$ is finite,what is its value?

samiul_samin
Posts:1007
Joined:Sat Dec 09, 2017 1:32 pm

Re: BdMO National Higher Secondary 2015#2

Unread post by samiul_samin » Fri Feb 22, 2019 11:32 am

$m^2+n^2=m^3 \rightarrow n^2=m^2(m-1)$
If $K$ is positive integer then plugging the value $m=K^2+1$ gives infinite solution for this equation .
So,$N$ is infinte.

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