Can the sum, difference and product of 2 numbers be perfect squares? [on hold]












2














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?










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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
















2














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?










share|improve this question









New contributor




Magic turtle is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.











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














2












2








2


0





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?










share|improve this question









New contributor




Magic turtle is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.











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






share|improve this question









New contributor




Magic turtle is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.











share|improve this question









New contributor




Magic turtle 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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edited yesterday







Magic turtle













New contributor




Magic turtle is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.









asked yesterday









Magic turtleMagic turtle

566




566




New contributor




Magic turtle is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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New contributor





Magic turtle is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.






Magic turtle is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.




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














  • 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










2 Answers
2






active

oldest

votes


















4














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.







share|improve this answer





















  • "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



















2














(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)







share|improve this answer























  • 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


















2 Answers
2






active

oldest

votes








2 Answers
2






active

oldest

votes









active

oldest

votes






active

oldest

votes









4














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.







share|improve this answer





















  • "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
















4














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.







share|improve this answer





















  • "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














4












4








4






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.







share|improve this answer












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.








share|improve this answer












share|improve this answer



share|improve this answer










answered yesterday









Gareth McCaughanGareth 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


















  • "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











2














(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)







share|improve this answer























  • 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
















2














(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)







share|improve this answer























  • 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














2












2








2






(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)







share|improve this answer














(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)








share|improve this answer














share|improve this answer



share|improve this answer








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


















  • 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



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