Product of n integers of AP is divisible by $n!$












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Prove that the product of the $n$ integers of an arithmetic progression of $n$ terms is divisible by $n!$ if common difference is relatively prime to $n!$.
First part of the question was to prove for d=1 which I was able to do using binomial coefficient. In this question though I am absolutely stumped.










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    $begingroup$


    Prove that the product of the $n$ integers of an arithmetic progression of $n$ terms is divisible by $n!$ if common difference is relatively prime to $n!$.
    First part of the question was to prove for d=1 which I was able to do using binomial coefficient. In this question though I am absolutely stumped.










    share|cite|improve this question









    $endgroup$















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      3








      3


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      $begingroup$


      Prove that the product of the $n$ integers of an arithmetic progression of $n$ terms is divisible by $n!$ if common difference is relatively prime to $n!$.
      First part of the question was to prove for d=1 which I was able to do using binomial coefficient. In this question though I am absolutely stumped.










      share|cite|improve this question









      $endgroup$




      Prove that the product of the $n$ integers of an arithmetic progression of $n$ terms is divisible by $n!$ if common difference is relatively prime to $n!$.
      First part of the question was to prove for d=1 which I was able to do using binomial coefficient. In this question though I am absolutely stumped.







      number-theory divisibility






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      asked Jan 29 at 7:45









      sn24sn24

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          Assume that the result is true for $d=1$, so $n!$ divides $(a+1)cdots(a+n)$ for any $a$. In modular mathematics, this is written as $(a+1)cdots(a+n)equiv 0pmod{n!}$.



          If $d$ is coprime to $n!$, then it is invertible, and has some inverse $c$, $cdequiv 1pmod{n!}$. So $$(a+d)(a+2d)cdots(a+nd)equiv d^n(ac+1)(ac+2)cdots(ac+n)equiv 0pmod{n!}$$






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            $begingroup$

            Assume that the result is true for $d=1$, so $n!$ divides $(a+1)cdots(a+n)$ for any $a$. In modular mathematics, this is written as $(a+1)cdots(a+n)equiv 0pmod{n!}$.



            If $d$ is coprime to $n!$, then it is invertible, and has some inverse $c$, $cdequiv 1pmod{n!}$. So $$(a+d)(a+2d)cdots(a+nd)equiv d^n(ac+1)(ac+2)cdots(ac+n)equiv 0pmod{n!}$$






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              $begingroup$

              Assume that the result is true for $d=1$, so $n!$ divides $(a+1)cdots(a+n)$ for any $a$. In modular mathematics, this is written as $(a+1)cdots(a+n)equiv 0pmod{n!}$.



              If $d$ is coprime to $n!$, then it is invertible, and has some inverse $c$, $cdequiv 1pmod{n!}$. So $$(a+d)(a+2d)cdots(a+nd)equiv d^n(ac+1)(ac+2)cdots(ac+n)equiv 0pmod{n!}$$






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                6












                6








                6





                $begingroup$

                Assume that the result is true for $d=1$, so $n!$ divides $(a+1)cdots(a+n)$ for any $a$. In modular mathematics, this is written as $(a+1)cdots(a+n)equiv 0pmod{n!}$.



                If $d$ is coprime to $n!$, then it is invertible, and has some inverse $c$, $cdequiv 1pmod{n!}$. So $$(a+d)(a+2d)cdots(a+nd)equiv d^n(ac+1)(ac+2)cdots(ac+n)equiv 0pmod{n!}$$






                share|cite|improve this answer











                $endgroup$



                Assume that the result is true for $d=1$, so $n!$ divides $(a+1)cdots(a+n)$ for any $a$. In modular mathematics, this is written as $(a+1)cdots(a+n)equiv 0pmod{n!}$.



                If $d$ is coprime to $n!$, then it is invertible, and has some inverse $c$, $cdequiv 1pmod{n!}$. So $$(a+d)(a+2d)cdots(a+nd)equiv d^n(ac+1)(ac+2)cdots(ac+n)equiv 0pmod{n!}$$







                share|cite|improve this answer














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                edited Jan 29 at 15:17









                J. W. Tanner

                4,0711320




                4,0711320










                answered Jan 29 at 9:40









                ChrystomathChrystomath

                1,898513




                1,898513






























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