How to prove the divergence of the sequence $(n!)^{1/n}$ [duplicate]












-1












$begingroup$



This question already has an answer here:




  • Analysis: Prove divergence of sequence $(n!)^{frac2n}$

    5 answers




How to prove that
$(n!)^{1/n}$ tends to infinity as $n$ tends to infinity ?










share|cite|improve this question











$endgroup$



marked as duplicate by José Carlos Santos, user416281, Michael Burr, Simply Beautiful Art, Crostul Jan 12 at 13:11


This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.























    -1












    $begingroup$



    This question already has an answer here:




    • Analysis: Prove divergence of sequence $(n!)^{frac2n}$

      5 answers




    How to prove that
    $(n!)^{1/n}$ tends to infinity as $n$ tends to infinity ?










    share|cite|improve this question











    $endgroup$



    marked as duplicate by José Carlos Santos, user416281, Michael Burr, Simply Beautiful Art, Crostul Jan 12 at 13:11


    This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.





















      -1












      -1








      -1


      1



      $begingroup$



      This question already has an answer here:




      • Analysis: Prove divergence of sequence $(n!)^{frac2n}$

        5 answers




      How to prove that
      $(n!)^{1/n}$ tends to infinity as $n$ tends to infinity ?










      share|cite|improve this question











      $endgroup$





      This question already has an answer here:




      • Analysis: Prove divergence of sequence $(n!)^{frac2n}$

        5 answers




      How to prove that
      $(n!)^{1/n}$ tends to infinity as $n$ tends to infinity ?





      This question already has an answer here:




      • Analysis: Prove divergence of sequence $(n!)^{frac2n}$

        5 answers








      real-analysis sequences-and-series






      share|cite|improve this question















      share|cite|improve this question













      share|cite|improve this question




      share|cite|improve this question








      edited Jan 12 at 12:36









      Mohamad Misto

      516214




      516214










      asked Jan 12 at 12:30









      Nilesh KhatriNilesh Khatri

      195




      195




      marked as duplicate by José Carlos Santos, user416281, Michael Burr, Simply Beautiful Art, Crostul Jan 12 at 13:11


      This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.









      marked as duplicate by José Carlos Santos, user416281, Michael Burr, Simply Beautiful Art, Crostul Jan 12 at 13:11


      This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.
























          2 Answers
          2






          active

          oldest

          votes


















          3












          $begingroup$

          Observe that
          $$
          n!>left(frac{n}{2}right)^{frac{n}{2}}.
          $$

          This observation follows from writing out $n!$ as $n(n-1)(n-2)dots2cdot 1$ and taking half of the factors, those of size at least $frac{n}{2}$.



          Therefore,
          $$
          (n!)^{frac{1}{n}}>left(left(frac{n}{2}right)^{frac{n}{2}}right)^{frac{1}{n}}=left(frac{n}{2}right)^{frac{1}{2}},
          $$

          which diverges.






          share|cite|improve this answer









          $endgroup$





















            1












            $begingroup$

            Let $k$ be any positive integer. $(n!)^{1/n} geq (k(k+1)cdots n)^{1/n} geq k^{(n-k+1)/n}$ for $n >k$. Can you see from this that $(n!)^{1/n} to infty$?.






            share|cite|improve this answer









            $endgroup$




















              2 Answers
              2






              active

              oldest

              votes








              2 Answers
              2






              active

              oldest

              votes









              active

              oldest

              votes






              active

              oldest

              votes









              3












              $begingroup$

              Observe that
              $$
              n!>left(frac{n}{2}right)^{frac{n}{2}}.
              $$

              This observation follows from writing out $n!$ as $n(n-1)(n-2)dots2cdot 1$ and taking half of the factors, those of size at least $frac{n}{2}$.



              Therefore,
              $$
              (n!)^{frac{1}{n}}>left(left(frac{n}{2}right)^{frac{n}{2}}right)^{frac{1}{n}}=left(frac{n}{2}right)^{frac{1}{2}},
              $$

              which diverges.






              share|cite|improve this answer









              $endgroup$


















                3












                $begingroup$

                Observe that
                $$
                n!>left(frac{n}{2}right)^{frac{n}{2}}.
                $$

                This observation follows from writing out $n!$ as $n(n-1)(n-2)dots2cdot 1$ and taking half of the factors, those of size at least $frac{n}{2}$.



                Therefore,
                $$
                (n!)^{frac{1}{n}}>left(left(frac{n}{2}right)^{frac{n}{2}}right)^{frac{1}{n}}=left(frac{n}{2}right)^{frac{1}{2}},
                $$

                which diverges.






                share|cite|improve this answer









                $endgroup$
















                  3












                  3








                  3





                  $begingroup$

                  Observe that
                  $$
                  n!>left(frac{n}{2}right)^{frac{n}{2}}.
                  $$

                  This observation follows from writing out $n!$ as $n(n-1)(n-2)dots2cdot 1$ and taking half of the factors, those of size at least $frac{n}{2}$.



                  Therefore,
                  $$
                  (n!)^{frac{1}{n}}>left(left(frac{n}{2}right)^{frac{n}{2}}right)^{frac{1}{n}}=left(frac{n}{2}right)^{frac{1}{2}},
                  $$

                  which diverges.






                  share|cite|improve this answer









                  $endgroup$



                  Observe that
                  $$
                  n!>left(frac{n}{2}right)^{frac{n}{2}}.
                  $$

                  This observation follows from writing out $n!$ as $n(n-1)(n-2)dots2cdot 1$ and taking half of the factors, those of size at least $frac{n}{2}$.



                  Therefore,
                  $$
                  (n!)^{frac{1}{n}}>left(left(frac{n}{2}right)^{frac{n}{2}}right)^{frac{1}{n}}=left(frac{n}{2}right)^{frac{1}{2}},
                  $$

                  which diverges.







                  share|cite|improve this answer












                  share|cite|improve this answer



                  share|cite|improve this answer










                  answered Jan 12 at 12:36









                  Michael BurrMichael Burr

                  27k23262




                  27k23262























                      1












                      $begingroup$

                      Let $k$ be any positive integer. $(n!)^{1/n} geq (k(k+1)cdots n)^{1/n} geq k^{(n-k+1)/n}$ for $n >k$. Can you see from this that $(n!)^{1/n} to infty$?.






                      share|cite|improve this answer









                      $endgroup$


















                        1












                        $begingroup$

                        Let $k$ be any positive integer. $(n!)^{1/n} geq (k(k+1)cdots n)^{1/n} geq k^{(n-k+1)/n}$ for $n >k$. Can you see from this that $(n!)^{1/n} to infty$?.






                        share|cite|improve this answer









                        $endgroup$
















                          1












                          1








                          1





                          $begingroup$

                          Let $k$ be any positive integer. $(n!)^{1/n} geq (k(k+1)cdots n)^{1/n} geq k^{(n-k+1)/n}$ for $n >k$. Can you see from this that $(n!)^{1/n} to infty$?.






                          share|cite|improve this answer









                          $endgroup$



                          Let $k$ be any positive integer. $(n!)^{1/n} geq (k(k+1)cdots n)^{1/n} geq k^{(n-k+1)/n}$ for $n >k$. Can you see from this that $(n!)^{1/n} to infty$?.







                          share|cite|improve this answer












                          share|cite|improve this answer



                          share|cite|improve this answer










                          answered Jan 12 at 12:35









                          Kavi Rama MurthyKavi Rama Murthy

                          66.9k53067




                          66.9k53067















                              Popular posts from this blog

                              Questions related to Moebius Transform of Characteristic Function of the Primes

                              List of scandals in India

                              Can not write log (Is /dev/pts mounted?) - openpty in Ubuntu-on-Windows?