the number $sqrt{1+5^n+6^n+11^n}$ is an integer [closed]











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How can i prove that $sqrt{1+5^n+6^n+11^n}$ is an integer??



PS : i shouldn't use induction










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closed as off-topic by amWhy, KReiser, Cesareo, Strants, Lord Shark the Unknown Nov 29 at 5:44


This question appears to be off-topic. The users who voted to close gave this specific reason:


  • "This question is missing context or other details: Please improve the question by providing additional context, which ideally includes your thoughts on the problem and any attempts you have made to solve it. This information helps others identify where you have difficulties and helps them write answers appropriate to your experience level." – amWhy, KReiser, Cesareo, Strants

If this question can be reworded to fit the rules in the help center, please edit the question.









  • 3




    It doesn't work for $n=1$. Sorry, it doesn't work for all $n in mathbb N$. As of now, $sqrt{23} notin mathbb Z$.
    – amWhy
    Nov 28 at 22:17












  • Does it even hold for $n=1$?
    – Quang Hoang
    Nov 28 at 22:17










  • sorry i have to remake my question !!
    – FADZA
    Nov 28 at 22:20















up vote
1
down vote

favorite












How can i prove that $sqrt{1+5^n+6^n+11^n}$ is an integer??



PS : i shouldn't use induction










share|cite|improve this question















closed as off-topic by amWhy, KReiser, Cesareo, Strants, Lord Shark the Unknown Nov 29 at 5:44


This question appears to be off-topic. The users who voted to close gave this specific reason:


  • "This question is missing context or other details: Please improve the question by providing additional context, which ideally includes your thoughts on the problem and any attempts you have made to solve it. This information helps others identify where you have difficulties and helps them write answers appropriate to your experience level." – amWhy, KReiser, Cesareo, Strants

If this question can be reworded to fit the rules in the help center, please edit the question.









  • 3




    It doesn't work for $n=1$. Sorry, it doesn't work for all $n in mathbb N$. As of now, $sqrt{23} notin mathbb Z$.
    – amWhy
    Nov 28 at 22:17












  • Does it even hold for $n=1$?
    – Quang Hoang
    Nov 28 at 22:17










  • sorry i have to remake my question !!
    – FADZA
    Nov 28 at 22:20













up vote
1
down vote

favorite









up vote
1
down vote

favorite











How can i prove that $sqrt{1+5^n+6^n+11^n}$ is an integer??



PS : i shouldn't use induction










share|cite|improve this question















How can i prove that $sqrt{1+5^n+6^n+11^n}$ is an integer??



PS : i shouldn't use induction







algebra-precalculus elementary-number-theory arithmetic






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Nov 28 at 22:32









amWhy

191k28224439




191k28224439










asked Nov 28 at 22:15









FADZA

274




274




closed as off-topic by amWhy, KReiser, Cesareo, Strants, Lord Shark the Unknown Nov 29 at 5:44


This question appears to be off-topic. The users who voted to close gave this specific reason:


  • "This question is missing context or other details: Please improve the question by providing additional context, which ideally includes your thoughts on the problem and any attempts you have made to solve it. This information helps others identify where you have difficulties and helps them write answers appropriate to your experience level." – amWhy, KReiser, Cesareo, Strants

If this question can be reworded to fit the rules in the help center, please edit the question.




closed as off-topic by amWhy, KReiser, Cesareo, Strants, Lord Shark the Unknown Nov 29 at 5:44


This question appears to be off-topic. The users who voted to close gave this specific reason:


  • "This question is missing context or other details: Please improve the question by providing additional context, which ideally includes your thoughts on the problem and any attempts you have made to solve it. This information helps others identify where you have difficulties and helps them write answers appropriate to your experience level." – amWhy, KReiser, Cesareo, Strants

If this question can be reworded to fit the rules in the help center, please edit the question.








  • 3




    It doesn't work for $n=1$. Sorry, it doesn't work for all $n in mathbb N$. As of now, $sqrt{23} notin mathbb Z$.
    – amWhy
    Nov 28 at 22:17












  • Does it even hold for $n=1$?
    – Quang Hoang
    Nov 28 at 22:17










  • sorry i have to remake my question !!
    – FADZA
    Nov 28 at 22:20














  • 3




    It doesn't work for $n=1$. Sorry, it doesn't work for all $n in mathbb N$. As of now, $sqrt{23} notin mathbb Z$.
    – amWhy
    Nov 28 at 22:17












  • Does it even hold for $n=1$?
    – Quang Hoang
    Nov 28 at 22:17










  • sorry i have to remake my question !!
    – FADZA
    Nov 28 at 22:20








3




3




It doesn't work for $n=1$. Sorry, it doesn't work for all $n in mathbb N$. As of now, $sqrt{23} notin mathbb Z$.
– amWhy
Nov 28 at 22:17






It doesn't work for $n=1$. Sorry, it doesn't work for all $n in mathbb N$. As of now, $sqrt{23} notin mathbb Z$.
– amWhy
Nov 28 at 22:17














Does it even hold for $n=1$?
– Quang Hoang
Nov 28 at 22:17




Does it even hold for $n=1$?
– Quang Hoang
Nov 28 at 22:17












sorry i have to remake my question !!
– FADZA
Nov 28 at 22:20




sorry i have to remake my question !!
– FADZA
Nov 28 at 22:20










1 Answer
1






active

oldest

votes

















up vote
6
down vote













$n > 0 Rightarrow 1+5^n+6^n+11^n equiv 3 mod 5,$ hence this is never an integer except when $n=0.$






share|cite|improve this answer





















  • can you please explain to me why did you choose mod 5 !!
    – FADZA
    Nov 28 at 22:47






  • 1




    @awiya I noticed the $5,$ then noticed that $11 equiv 6 equiv 1 bmod 5.$
    – Display name
    Nov 28 at 22:50












  • get it ... thank you @Display name
    – FADZA
    Nov 28 at 22:56


















1 Answer
1






active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes








up vote
6
down vote













$n > 0 Rightarrow 1+5^n+6^n+11^n equiv 3 mod 5,$ hence this is never an integer except when $n=0.$






share|cite|improve this answer





















  • can you please explain to me why did you choose mod 5 !!
    – FADZA
    Nov 28 at 22:47






  • 1




    @awiya I noticed the $5,$ then noticed that $11 equiv 6 equiv 1 bmod 5.$
    – Display name
    Nov 28 at 22:50












  • get it ... thank you @Display name
    – FADZA
    Nov 28 at 22:56















up vote
6
down vote













$n > 0 Rightarrow 1+5^n+6^n+11^n equiv 3 mod 5,$ hence this is never an integer except when $n=0.$






share|cite|improve this answer





















  • can you please explain to me why did you choose mod 5 !!
    – FADZA
    Nov 28 at 22:47






  • 1




    @awiya I noticed the $5,$ then noticed that $11 equiv 6 equiv 1 bmod 5.$
    – Display name
    Nov 28 at 22:50












  • get it ... thank you @Display name
    – FADZA
    Nov 28 at 22:56













up vote
6
down vote










up vote
6
down vote









$n > 0 Rightarrow 1+5^n+6^n+11^n equiv 3 mod 5,$ hence this is never an integer except when $n=0.$






share|cite|improve this answer












$n > 0 Rightarrow 1+5^n+6^n+11^n equiv 3 mod 5,$ hence this is never an integer except when $n=0.$







share|cite|improve this answer












share|cite|improve this answer



share|cite|improve this answer










answered Nov 28 at 22:27









Display name

789313




789313












  • can you please explain to me why did you choose mod 5 !!
    – FADZA
    Nov 28 at 22:47






  • 1




    @awiya I noticed the $5,$ then noticed that $11 equiv 6 equiv 1 bmod 5.$
    – Display name
    Nov 28 at 22:50












  • get it ... thank you @Display name
    – FADZA
    Nov 28 at 22:56


















  • can you please explain to me why did you choose mod 5 !!
    – FADZA
    Nov 28 at 22:47






  • 1




    @awiya I noticed the $5,$ then noticed that $11 equiv 6 equiv 1 bmod 5.$
    – Display name
    Nov 28 at 22:50












  • get it ... thank you @Display name
    – FADZA
    Nov 28 at 22:56
















can you please explain to me why did you choose mod 5 !!
– FADZA
Nov 28 at 22:47




can you please explain to me why did you choose mod 5 !!
– FADZA
Nov 28 at 22:47




1




1




@awiya I noticed the $5,$ then noticed that $11 equiv 6 equiv 1 bmod 5.$
– Display name
Nov 28 at 22:50






@awiya I noticed the $5,$ then noticed that $11 equiv 6 equiv 1 bmod 5.$
– Display name
Nov 28 at 22:50














get it ... thank you @Display name
– FADZA
Nov 28 at 22:56




get it ... thank you @Display name
– FADZA
Nov 28 at 22:56



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