Finding integer solution to a quadratic equation in two unknowns
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We have an equation:
$$m^2 = n^2 + m + n + 2018.$$
Find all integer pairs $(m,n)$ satisfying this equation.
elementary-number-theory divisibility diophantine-equations
New contributor
BIDS Salvaterra is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
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add a comment |
$begingroup$
We have an equation:
$$m^2 = n^2 + m + n + 2018.$$
Find all integer pairs $(m,n)$ satisfying this equation.
elementary-number-theory divisibility diophantine-equations
New contributor
BIDS Salvaterra is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
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1
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Well, if $(m,n)$ is a solutions, integer or not, what is the formula for $m$ in terms of $n$ (or vice versa)? Now which values can to be integers.
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– fleablood
4 hours ago
add a comment |
$begingroup$
We have an equation:
$$m^2 = n^2 + m + n + 2018.$$
Find all integer pairs $(m,n)$ satisfying this equation.
elementary-number-theory divisibility diophantine-equations
New contributor
BIDS Salvaterra is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
We have an equation:
$$m^2 = n^2 + m + n + 2018.$$
Find all integer pairs $(m,n)$ satisfying this equation.
elementary-number-theory divisibility diophantine-equations
elementary-number-theory divisibility diophantine-equations
New contributor
BIDS Salvaterra is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
BIDS Salvaterra is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 3 hours ago
greedoid
46.3k1160117
46.3k1160117
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BIDS Salvaterra is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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asked 4 hours ago
BIDS SalvaterraBIDS Salvaterra
91
91
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BIDS Salvaterra is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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New contributor
BIDS Salvaterra is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
BIDS Salvaterra is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
1
$begingroup$
Well, if $(m,n)$ is a solutions, integer or not, what is the formula for $m$ in terms of $n$ (or vice versa)? Now which values can to be integers.
$endgroup$
– fleablood
4 hours ago
add a comment |
1
$begingroup$
Well, if $(m,n)$ is a solutions, integer or not, what is the formula for $m$ in terms of $n$ (or vice versa)? Now which values can to be integers.
$endgroup$
– fleablood
4 hours ago
1
1
$begingroup$
Well, if $(m,n)$ is a solutions, integer or not, what is the formula for $m$ in terms of $n$ (or vice versa)? Now which values can to be integers.
$endgroup$
– fleablood
4 hours ago
$begingroup$
Well, if $(m,n)$ is a solutions, integer or not, what is the formula for $m$ in terms of $n$ (or vice versa)? Now which values can to be integers.
$endgroup$
– fleablood
4 hours ago
add a comment |
3 Answers
3
active
oldest
votes
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Hint $$ (m+n)(m-n)= (m+n)+2018$$
so $$ (m+n)(m-n-1)= 2018$$
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$begingroup$
Guide: Write $m=n+k$ for some integer $k$, then $$n^2+2nk+k^2= n^2+2n+k+2018$$
so $$ n={-k^2+k+2018over 2(k-1)}=-{kover 2}+{1009over k-1}$$
If $k$ is odd then there is no solution, so $k= 2s$ so $$2s-1mid 1009$$
Can you finish?
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add a comment |
$begingroup$
Simpler start: separating variables to either side gives:
$$m^2-m=n^2+n+2018$$
which then factors roughly for the variables as:
$$m(m-1)=n(n+1)+2018$$
which since both pairs(m,m-1) and (n,n-1) are consecutive integers, you can divide both sides by two giving:
$$frac{m(m-1)}{2}=frac{n(n+1)}{2}+1009$$
But, $frac{y(y+1)}{2}$ is the form of the y-th triangular number, so the solutions are such that 1009 is the difference of two triangular numbers $T_{vert m-1 vert}$ and $T_{vert n vert}$ . Solve for n, and m-1 .
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3 Answers
3
active
oldest
votes
3 Answers
3
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
Hint $$ (m+n)(m-n)= (m+n)+2018$$
so $$ (m+n)(m-n-1)= 2018$$
$endgroup$
add a comment |
$begingroup$
Hint $$ (m+n)(m-n)= (m+n)+2018$$
so $$ (m+n)(m-n-1)= 2018$$
$endgroup$
add a comment |
$begingroup$
Hint $$ (m+n)(m-n)= (m+n)+2018$$
so $$ (m+n)(m-n-1)= 2018$$
$endgroup$
Hint $$ (m+n)(m-n)= (m+n)+2018$$
so $$ (m+n)(m-n-1)= 2018$$
answered 4 hours ago
greedoidgreedoid
46.3k1160117
46.3k1160117
add a comment |
add a comment |
$begingroup$
Guide: Write $m=n+k$ for some integer $k$, then $$n^2+2nk+k^2= n^2+2n+k+2018$$
so $$ n={-k^2+k+2018over 2(k-1)}=-{kover 2}+{1009over k-1}$$
If $k$ is odd then there is no solution, so $k= 2s$ so $$2s-1mid 1009$$
Can you finish?
$endgroup$
add a comment |
$begingroup$
Guide: Write $m=n+k$ for some integer $k$, then $$n^2+2nk+k^2= n^2+2n+k+2018$$
so $$ n={-k^2+k+2018over 2(k-1)}=-{kover 2}+{1009over k-1}$$
If $k$ is odd then there is no solution, so $k= 2s$ so $$2s-1mid 1009$$
Can you finish?
$endgroup$
add a comment |
$begingroup$
Guide: Write $m=n+k$ for some integer $k$, then $$n^2+2nk+k^2= n^2+2n+k+2018$$
so $$ n={-k^2+k+2018over 2(k-1)}=-{kover 2}+{1009over k-1}$$
If $k$ is odd then there is no solution, so $k= 2s$ so $$2s-1mid 1009$$
Can you finish?
$endgroup$
Guide: Write $m=n+k$ for some integer $k$, then $$n^2+2nk+k^2= n^2+2n+k+2018$$
so $$ n={-k^2+k+2018over 2(k-1)}=-{kover 2}+{1009over k-1}$$
If $k$ is odd then there is no solution, so $k= 2s$ so $$2s-1mid 1009$$
Can you finish?
answered 4 hours ago
greedoidgreedoid
46.3k1160117
46.3k1160117
add a comment |
add a comment |
$begingroup$
Simpler start: separating variables to either side gives:
$$m^2-m=n^2+n+2018$$
which then factors roughly for the variables as:
$$m(m-1)=n(n+1)+2018$$
which since both pairs(m,m-1) and (n,n-1) are consecutive integers, you can divide both sides by two giving:
$$frac{m(m-1)}{2}=frac{n(n+1)}{2}+1009$$
But, $frac{y(y+1)}{2}$ is the form of the y-th triangular number, so the solutions are such that 1009 is the difference of two triangular numbers $T_{vert m-1 vert}$ and $T_{vert n vert}$ . Solve for n, and m-1 .
$endgroup$
add a comment |
$begingroup$
Simpler start: separating variables to either side gives:
$$m^2-m=n^2+n+2018$$
which then factors roughly for the variables as:
$$m(m-1)=n(n+1)+2018$$
which since both pairs(m,m-1) and (n,n-1) are consecutive integers, you can divide both sides by two giving:
$$frac{m(m-1)}{2}=frac{n(n+1)}{2}+1009$$
But, $frac{y(y+1)}{2}$ is the form of the y-th triangular number, so the solutions are such that 1009 is the difference of two triangular numbers $T_{vert m-1 vert}$ and $T_{vert n vert}$ . Solve for n, and m-1 .
$endgroup$
add a comment |
$begingroup$
Simpler start: separating variables to either side gives:
$$m^2-m=n^2+n+2018$$
which then factors roughly for the variables as:
$$m(m-1)=n(n+1)+2018$$
which since both pairs(m,m-1) and (n,n-1) are consecutive integers, you can divide both sides by two giving:
$$frac{m(m-1)}{2}=frac{n(n+1)}{2}+1009$$
But, $frac{y(y+1)}{2}$ is the form of the y-th triangular number, so the solutions are such that 1009 is the difference of two triangular numbers $T_{vert m-1 vert}$ and $T_{vert n vert}$ . Solve for n, and m-1 .
$endgroup$
Simpler start: separating variables to either side gives:
$$m^2-m=n^2+n+2018$$
which then factors roughly for the variables as:
$$m(m-1)=n(n+1)+2018$$
which since both pairs(m,m-1) and (n,n-1) are consecutive integers, you can divide both sides by two giving:
$$frac{m(m-1)}{2}=frac{n(n+1)}{2}+1009$$
But, $frac{y(y+1)}{2}$ is the form of the y-th triangular number, so the solutions are such that 1009 is the difference of two triangular numbers $T_{vert m-1 vert}$ and $T_{vert n vert}$ . Solve for n, and m-1 .
answered 2 hours ago
Roddy MacPheeRoddy MacPhee
22414
22414
add a comment |
add a comment |
BIDS Salvaterra is a new contributor. Be nice, and check out our Code of Conduct.
BIDS Salvaterra is a new contributor. Be nice, and check out our Code of Conduct.
BIDS Salvaterra is a new contributor. Be nice, and check out our Code of Conduct.
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1
$begingroup$
Well, if $(m,n)$ is a solutions, integer or not, what is the formula for $m$ in terms of $n$ (or vice versa)? Now which values can to be integers.
$endgroup$
– fleablood
4 hours ago