Can the sum, difference and product of 2 numbers be perfect squares? [on hold]
If we take 2 numbers $x$ and $y$ such that $x>y>0$ and , can $x + y$, $x - y$ and $xy$ all be perfect squares?
mathematics number-theory algebra
New contributor
put on hold as off-topic by rhsquared, Glorfindel, JonMark Perry, Excited Raichu, ABcDexter yesterday
This question appears to be off-topic. The users who voted to close gave this specific reason:
- "This question is off-topic as it appears to be a mathematics problem, as opposed to a mathematical puzzle. For more info, see "Are math-textbook-style problems on topic?" on meta." – rhsquared, Glorfindel, JonMark Perry, Excited Raichu, ABcDexter
If this question can be reworded to fit the rules in the help center, please edit the question.
add a comment |
If we take 2 numbers $x$ and $y$ such that $x>y>0$ and , can $x + y$, $x - y$ and $xy$ all be perfect squares?
mathematics number-theory algebra
New contributor
put on hold as off-topic by rhsquared, Glorfindel, JonMark Perry, Excited Raichu, ABcDexter yesterday
This question appears to be off-topic. The users who voted to close gave this specific reason:
- "This question is off-topic as it appears to be a mathematics problem, as opposed to a mathematical puzzle. For more info, see "Are math-textbook-style problems on topic?" on meta." – rhsquared, Glorfindel, JonMark Perry, Excited Raichu, ABcDexter
If this question can be reworded to fit the rules in the help center, please edit the question.
1
Is this on topic? Feels like a math question
– Dr Xorile
yesterday
No I made it myself but could not solve it.
– Magic turtle
yesterday
add a comment |
If we take 2 numbers $x$ and $y$ such that $x>y>0$ and , can $x + y$, $x - y$ and $xy$ all be perfect squares?
mathematics number-theory algebra
New contributor
If we take 2 numbers $x$ and $y$ such that $x>y>0$ and , can $x + y$, $x - y$ and $xy$ all be perfect squares?
mathematics number-theory algebra
mathematics number-theory algebra
New contributor
New contributor
edited yesterday
Magic turtle
New contributor
asked yesterday
Magic turtleMagic turtle
566
566
New contributor
New contributor
put on hold as off-topic by rhsquared, Glorfindel, JonMark Perry, Excited Raichu, ABcDexter yesterday
This question appears to be off-topic. The users who voted to close gave this specific reason:
- "This question is off-topic as it appears to be a mathematics problem, as opposed to a mathematical puzzle. For more info, see "Are math-textbook-style problems on topic?" on meta." – rhsquared, Glorfindel, JonMark Perry, Excited Raichu, ABcDexter
If this question can be reworded to fit the rules in the help center, please edit the question.
put on hold as off-topic by rhsquared, Glorfindel, JonMark Perry, Excited Raichu, ABcDexter yesterday
This question appears to be off-topic. The users who voted to close gave this specific reason:
- "This question is off-topic as it appears to be a mathematics problem, as opposed to a mathematical puzzle. For more info, see "Are math-textbook-style problems on topic?" on meta." – rhsquared, Glorfindel, JonMark Perry, Excited Raichu, ABcDexter
If this question can be reworded to fit the rules in the help center, please edit the question.
1
Is this on topic? Feels like a math question
– Dr Xorile
yesterday
No I made it myself but could not solve it.
– Magic turtle
yesterday
add a comment |
1
Is this on topic? Feels like a math question
– Dr Xorile
yesterday
No I made it myself but could not solve it.
– Magic turtle
yesterday
1
1
Is this on topic? Feels like a math question
– Dr Xorile
yesterday
Is this on topic? Feels like a math question
– Dr Xorile
yesterday
No I made it myself but could not solve it.
– Magic turtle
yesterday
No I made it myself but could not solve it.
– Magic turtle
yesterday
add a comment |
2 Answers
2
active
oldest
votes
The answer is
that they cannot.
Suppose $x+y=a^2$ and $x-y=b^2$. Then
$x,y=frac{a^2pm b^2}2$ and therefore $4xy=a^4-b^4$. So if this too is a square we have $a^4-b^4=c^2$. Now see https://math.stackexchange.com/questions/153546/solving-x4-y4-z2 where it is shown that there are no solutions to this equation in nonzero integers.
"if this too is a square" we have (a^4 -b^4) / 4 = c^2 ... The fact that you binned y=0 means that the proof doesn't hold for this alternate equation
– UKMonkey
yesterday
If 4xy is a square then xy is also a square. I'm not sure what you mean by "you binned y=0" but the question itself specifies that y>0.
– Gareth McCaughan♦
yesterday
add a comment |
(Before the OP clarifying that 0 is disallowed)
Yes.
x = 4, y = 0; x+y = 4, x-y = 4, xy = 0. (x can be any perfect square, I just decided to use 4)
Sorry my fault, I meant to include that y cannot = 0.
– Magic turtle
yesterday
But can x be 0?
– Ian MacDonald
yesterday
If x were 0 y would be less than 0 making x + y negative and a negative number cannot be a perfect square
– Magic turtle
yesterday
add a comment |
2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
The answer is
that they cannot.
Suppose $x+y=a^2$ and $x-y=b^2$. Then
$x,y=frac{a^2pm b^2}2$ and therefore $4xy=a^4-b^4$. So if this too is a square we have $a^4-b^4=c^2$. Now see https://math.stackexchange.com/questions/153546/solving-x4-y4-z2 where it is shown that there are no solutions to this equation in nonzero integers.
"if this too is a square" we have (a^4 -b^4) / 4 = c^2 ... The fact that you binned y=0 means that the proof doesn't hold for this alternate equation
– UKMonkey
yesterday
If 4xy is a square then xy is also a square. I'm not sure what you mean by "you binned y=0" but the question itself specifies that y>0.
– Gareth McCaughan♦
yesterday
add a comment |
The answer is
that they cannot.
Suppose $x+y=a^2$ and $x-y=b^2$. Then
$x,y=frac{a^2pm b^2}2$ and therefore $4xy=a^4-b^4$. So if this too is a square we have $a^4-b^4=c^2$. Now see https://math.stackexchange.com/questions/153546/solving-x4-y4-z2 where it is shown that there are no solutions to this equation in nonzero integers.
"if this too is a square" we have (a^4 -b^4) / 4 = c^2 ... The fact that you binned y=0 means that the proof doesn't hold for this alternate equation
– UKMonkey
yesterday
If 4xy is a square then xy is also a square. I'm not sure what you mean by "you binned y=0" but the question itself specifies that y>0.
– Gareth McCaughan♦
yesterday
add a comment |
The answer is
that they cannot.
Suppose $x+y=a^2$ and $x-y=b^2$. Then
$x,y=frac{a^2pm b^2}2$ and therefore $4xy=a^4-b^4$. So if this too is a square we have $a^4-b^4=c^2$. Now see https://math.stackexchange.com/questions/153546/solving-x4-y4-z2 where it is shown that there are no solutions to this equation in nonzero integers.
The answer is
that they cannot.
Suppose $x+y=a^2$ and $x-y=b^2$. Then
$x,y=frac{a^2pm b^2}2$ and therefore $4xy=a^4-b^4$. So if this too is a square we have $a^4-b^4=c^2$. Now see https://math.stackexchange.com/questions/153546/solving-x4-y4-z2 where it is shown that there are no solutions to this equation in nonzero integers.
answered yesterday
Gareth McCaughan♦Gareth McCaughan
60.7k3152235
60.7k3152235
"if this too is a square" we have (a^4 -b^4) / 4 = c^2 ... The fact that you binned y=0 means that the proof doesn't hold for this alternate equation
– UKMonkey
yesterday
If 4xy is a square then xy is also a square. I'm not sure what you mean by "you binned y=0" but the question itself specifies that y>0.
– Gareth McCaughan♦
yesterday
add a comment |
"if this too is a square" we have (a^4 -b^4) / 4 = c^2 ... The fact that you binned y=0 means that the proof doesn't hold for this alternate equation
– UKMonkey
yesterday
If 4xy is a square then xy is also a square. I'm not sure what you mean by "you binned y=0" but the question itself specifies that y>0.
– Gareth McCaughan♦
yesterday
"if this too is a square" we have (a^4 -b^4) / 4 = c^2 ... The fact that you binned y=0 means that the proof doesn't hold for this alternate equation
– UKMonkey
yesterday
"if this too is a square" we have (a^4 -b^4) / 4 = c^2 ... The fact that you binned y=0 means that the proof doesn't hold for this alternate equation
– UKMonkey
yesterday
If 4xy is a square then xy is also a square. I'm not sure what you mean by "you binned y=0" but the question itself specifies that y>0.
– Gareth McCaughan♦
yesterday
If 4xy is a square then xy is also a square. I'm not sure what you mean by "you binned y=0" but the question itself specifies that y>0.
– Gareth McCaughan♦
yesterday
add a comment |
(Before the OP clarifying that 0 is disallowed)
Yes.
x = 4, y = 0; x+y = 4, x-y = 4, xy = 0. (x can be any perfect square, I just decided to use 4)
Sorry my fault, I meant to include that y cannot = 0.
– Magic turtle
yesterday
But can x be 0?
– Ian MacDonald
yesterday
If x were 0 y would be less than 0 making x + y negative and a negative number cannot be a perfect square
– Magic turtle
yesterday
add a comment |
(Before the OP clarifying that 0 is disallowed)
Yes.
x = 4, y = 0; x+y = 4, x-y = 4, xy = 0. (x can be any perfect square, I just decided to use 4)
Sorry my fault, I meant to include that y cannot = 0.
– Magic turtle
yesterday
But can x be 0?
– Ian MacDonald
yesterday
If x were 0 y would be less than 0 making x + y negative and a negative number cannot be a perfect square
– Magic turtle
yesterday
add a comment |
(Before the OP clarifying that 0 is disallowed)
Yes.
x = 4, y = 0; x+y = 4, x-y = 4, xy = 0. (x can be any perfect square, I just decided to use 4)
(Before the OP clarifying that 0 is disallowed)
Yes.
x = 4, y = 0; x+y = 4, x-y = 4, xy = 0. (x can be any perfect square, I just decided to use 4)
edited yesterday
answered yesterday
Excited RaichuExcited Raichu
6,11821065
6,11821065
Sorry my fault, I meant to include that y cannot = 0.
– Magic turtle
yesterday
But can x be 0?
– Ian MacDonald
yesterday
If x were 0 y would be less than 0 making x + y negative and a negative number cannot be a perfect square
– Magic turtle
yesterday
add a comment |
Sorry my fault, I meant to include that y cannot = 0.
– Magic turtle
yesterday
But can x be 0?
– Ian MacDonald
yesterday
If x were 0 y would be less than 0 making x + y negative and a negative number cannot be a perfect square
– Magic turtle
yesterday
Sorry my fault, I meant to include that y cannot = 0.
– Magic turtle
yesterday
Sorry my fault, I meant to include that y cannot = 0.
– Magic turtle
yesterday
But can x be 0?
– Ian MacDonald
yesterday
But can x be 0?
– Ian MacDonald
yesterday
If x were 0 y would be less than 0 making x + y negative and a negative number cannot be a perfect square
– Magic turtle
yesterday
If x were 0 y would be less than 0 making x + y negative and a negative number cannot be a perfect square
– Magic turtle
yesterday
add a comment |
1
Is this on topic? Feels like a math question
– Dr Xorile
yesterday
No I made it myself but could not solve it.
– Magic turtle
yesterday