Help on induction, couldn't make both side the same value

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$$sum_k=1^n k(k+1)(k+2)...(k+p-1)= fracn(n+1)(n+2)...(n+p) p+1 $$
Induction g(n+1)=f(n+1)+g(n) sub n+1

(1)$$(n+1)(n+2)...(n+p)(p+1)+fracn(n+1)(n+2)...(n+p) p+1(p+1) $$
(2)
$$frac(n+1)(n+2)...(n+1+p) p+1(p+1)$$
make (1)=(2)
$$(n+p)!(p+1)+(n+p)!=(n+1+p)! $$



I then couldnt make the R.H.S==L.H.S







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    $$sum_k=1^n k(k+1)(k+2)...(k+p-1)= fracn(n+1)(n+2)...(n+p) p+1 $$
    Induction g(n+1)=f(n+1)+g(n) sub n+1

    (1)$$(n+1)(n+2)...(n+p)(p+1)+fracn(n+1)(n+2)...(n+p) p+1(p+1) $$
    (2)
    $$frac(n+1)(n+2)...(n+1+p) p+1(p+1)$$
    make (1)=(2)
    $$(n+p)!(p+1)+(n+p)!=(n+1+p)! $$



    I then couldnt make the R.H.S==L.H.S







    share|cite|improve this question





















      up vote
      0
      down vote

      favorite









      up vote
      0
      down vote

      favorite











      $$sum_k=1^n k(k+1)(k+2)...(k+p-1)= fracn(n+1)(n+2)...(n+p) p+1 $$
      Induction g(n+1)=f(n+1)+g(n) sub n+1

      (1)$$(n+1)(n+2)...(n+p)(p+1)+fracn(n+1)(n+2)...(n+p) p+1(p+1) $$
      (2)
      $$frac(n+1)(n+2)...(n+1+p) p+1(p+1)$$
      make (1)=(2)
      $$(n+p)!(p+1)+(n+p)!=(n+1+p)! $$



      I then couldnt make the R.H.S==L.H.S







      share|cite|improve this question











      $$sum_k=1^n k(k+1)(k+2)...(k+p-1)= fracn(n+1)(n+2)...(n+p) p+1 $$
      Induction g(n+1)=f(n+1)+g(n) sub n+1

      (1)$$(n+1)(n+2)...(n+p)(p+1)+fracn(n+1)(n+2)...(n+p) p+1(p+1) $$
      (2)
      $$frac(n+1)(n+2)...(n+1+p) p+1(p+1)$$
      make (1)=(2)
      $$(n+p)!(p+1)+(n+p)!=(n+1+p)! $$



      I then couldnt make the R.H.S==L.H.S









      share|cite|improve this question










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      asked Jul 21 at 17:48









      stevie lol

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          2 Answers
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          accepted










          $$sum_k=1^n k(k+1)(k+2)...(k+p-1)~=~fracn(n+1)(n+2)...(n+p) p+1 $$



          First of all this given sum can be simplified by using factorials



          $$frac(n+p)!(n-1)!~=~n(n+1)(n+2)cdots(n+p)$$



          In general the term



          $$(x,n)~=~x^overlinen~=~frac(x+n+1)!(x+1)!$$
          is called Pochhammer symbol or rising factorial.
          $$beginalignsum_k=1^n frac(k+p-1)!(k-1)!~&=~fracn(n+1)(n+2)...(n+p) p+1\~&=~frac(n+p)!(n-1)!(p+1)endalign$$
          $$beginalignsum_k=1^n+1 frac(k+p-1)!(k-1)!~&=~frac(n+1)(n+2)(n+3)...(n+p+1) p+1\~&=~frac(n+p+1)!n!(p+1)endalign$$
          $$beginalignsum_k=1^n+1 frac(k+p-1)!(k-1)!~=~&sum_k=1^n frac(k+p-1)!(k-1)!~+~frac(n+p)n!endalign$$
          $$beginalignsum_k=1^n frac(k+p-1)!(k-1)!~+~frac(n+p)!n!~&=~frac(n+p)!(n-1)!(p+1)~+~frac(n+p)!n!\&=~fracn(n+p)!+(p+1)(n+p)!n!(p+1)\&=~frac(n+p+1)(n+p)!n!(p+1)\&=~frac(n+p+1)!n!(p+1)endalign$$



          Maybe this slightly different approach to your problem can help you to get further.






          share|cite|improve this answer























          • Do u mind explaining why when u multiply n! to (n+p)! why it renders to n(n+p)!
            – stevie lol
            Jul 21 at 18:50











          • I never multiplied $(n+p)!$ ny $n!$. I used the fact that $n!=n(n-1)!$. While the final denominator of the fraction is $n!(p+1)$ I have to multiply the first fraction by $fracnn$ and the second one by $fracp+1p+1$.
            – mrtaurho
            Jul 21 at 18:53










          • Sry for asking a stupid question, but how did u get rid (n-1)! from the denominator and render it to n!(p+1)?
            – stevie lol
            Jul 21 at 19:06










          • There is no problem in further asking :) $Big |$$frac(n+p)!(n-1)!(p+1)fracnn~=~fracn(n+p)!n(n-1)!(p+1)$ which is equal to $fracn(n+p)!n!(p+1)$ by the functional equation of the factorial $n!~=~n(n-1)!$
            – mrtaurho
            Jul 21 at 19:09


















          up vote
          0
          down vote













          I'm not sure how or why you are writing 1).



          Just do the following.



          Assuming that $sum_k=1^n k(k+1)(k+2)...(k+p-1)= fracn(n+1)(n+2)...(n+p) p+1$



          Then $sum_k=1^n+1k(k+1)...(k+p-1) = [sum_k=1^n k(k+1)...(k+p-1)]+ (n+1)((n+1)+1)...((n+1)+p-1)$



          $= fracn(n+1)...(n+p) p+1 + (n+1)(n+2)....(n+p-1)(n+p)$



          $= [(n+1)(n+2).....(n+p)](frac np+1 + 1)$



          $=[(n+1)(n+2).....(n+p)](frac np+1 + fracp+1p+1)$



          $=[(n+1)(n+2).....(n+p)](frac n+p + 1p+1)$



          $=frac (n+1).....(n+1 + p)p+1$






          share|cite|improve this answer





















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            2 Answers
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            active

            oldest

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            2 Answers
            2






            active

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            active

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            active

            oldest

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            up vote
            2
            down vote



            accepted










            $$sum_k=1^n k(k+1)(k+2)...(k+p-1)~=~fracn(n+1)(n+2)...(n+p) p+1 $$



            First of all this given sum can be simplified by using factorials



            $$frac(n+p)!(n-1)!~=~n(n+1)(n+2)cdots(n+p)$$



            In general the term



            $$(x,n)~=~x^overlinen~=~frac(x+n+1)!(x+1)!$$
            is called Pochhammer symbol or rising factorial.
            $$beginalignsum_k=1^n frac(k+p-1)!(k-1)!~&=~fracn(n+1)(n+2)...(n+p) p+1\~&=~frac(n+p)!(n-1)!(p+1)endalign$$
            $$beginalignsum_k=1^n+1 frac(k+p-1)!(k-1)!~&=~frac(n+1)(n+2)(n+3)...(n+p+1) p+1\~&=~frac(n+p+1)!n!(p+1)endalign$$
            $$beginalignsum_k=1^n+1 frac(k+p-1)!(k-1)!~=~&sum_k=1^n frac(k+p-1)!(k-1)!~+~frac(n+p)n!endalign$$
            $$beginalignsum_k=1^n frac(k+p-1)!(k-1)!~+~frac(n+p)!n!~&=~frac(n+p)!(n-1)!(p+1)~+~frac(n+p)!n!\&=~fracn(n+p)!+(p+1)(n+p)!n!(p+1)\&=~frac(n+p+1)(n+p)!n!(p+1)\&=~frac(n+p+1)!n!(p+1)endalign$$



            Maybe this slightly different approach to your problem can help you to get further.






            share|cite|improve this answer























            • Do u mind explaining why when u multiply n! to (n+p)! why it renders to n(n+p)!
              – stevie lol
              Jul 21 at 18:50











            • I never multiplied $(n+p)!$ ny $n!$. I used the fact that $n!=n(n-1)!$. While the final denominator of the fraction is $n!(p+1)$ I have to multiply the first fraction by $fracnn$ and the second one by $fracp+1p+1$.
              – mrtaurho
              Jul 21 at 18:53










            • Sry for asking a stupid question, but how did u get rid (n-1)! from the denominator and render it to n!(p+1)?
              – stevie lol
              Jul 21 at 19:06










            • There is no problem in further asking :) $Big |$$frac(n+p)!(n-1)!(p+1)fracnn~=~fracn(n+p)!n(n-1)!(p+1)$ which is equal to $fracn(n+p)!n!(p+1)$ by the functional equation of the factorial $n!~=~n(n-1)!$
              – mrtaurho
              Jul 21 at 19:09















            up vote
            2
            down vote



            accepted










            $$sum_k=1^n k(k+1)(k+2)...(k+p-1)~=~fracn(n+1)(n+2)...(n+p) p+1 $$



            First of all this given sum can be simplified by using factorials



            $$frac(n+p)!(n-1)!~=~n(n+1)(n+2)cdots(n+p)$$



            In general the term



            $$(x,n)~=~x^overlinen~=~frac(x+n+1)!(x+1)!$$
            is called Pochhammer symbol or rising factorial.
            $$beginalignsum_k=1^n frac(k+p-1)!(k-1)!~&=~fracn(n+1)(n+2)...(n+p) p+1\~&=~frac(n+p)!(n-1)!(p+1)endalign$$
            $$beginalignsum_k=1^n+1 frac(k+p-1)!(k-1)!~&=~frac(n+1)(n+2)(n+3)...(n+p+1) p+1\~&=~frac(n+p+1)!n!(p+1)endalign$$
            $$beginalignsum_k=1^n+1 frac(k+p-1)!(k-1)!~=~&sum_k=1^n frac(k+p-1)!(k-1)!~+~frac(n+p)n!endalign$$
            $$beginalignsum_k=1^n frac(k+p-1)!(k-1)!~+~frac(n+p)!n!~&=~frac(n+p)!(n-1)!(p+1)~+~frac(n+p)!n!\&=~fracn(n+p)!+(p+1)(n+p)!n!(p+1)\&=~frac(n+p+1)(n+p)!n!(p+1)\&=~frac(n+p+1)!n!(p+1)endalign$$



            Maybe this slightly different approach to your problem can help you to get further.






            share|cite|improve this answer























            • Do u mind explaining why when u multiply n! to (n+p)! why it renders to n(n+p)!
              – stevie lol
              Jul 21 at 18:50











            • I never multiplied $(n+p)!$ ny $n!$. I used the fact that $n!=n(n-1)!$. While the final denominator of the fraction is $n!(p+1)$ I have to multiply the first fraction by $fracnn$ and the second one by $fracp+1p+1$.
              – mrtaurho
              Jul 21 at 18:53










            • Sry for asking a stupid question, but how did u get rid (n-1)! from the denominator and render it to n!(p+1)?
              – stevie lol
              Jul 21 at 19:06










            • There is no problem in further asking :) $Big |$$frac(n+p)!(n-1)!(p+1)fracnn~=~fracn(n+p)!n(n-1)!(p+1)$ which is equal to $fracn(n+p)!n!(p+1)$ by the functional equation of the factorial $n!~=~n(n-1)!$
              – mrtaurho
              Jul 21 at 19:09













            up vote
            2
            down vote



            accepted







            up vote
            2
            down vote



            accepted






            $$sum_k=1^n k(k+1)(k+2)...(k+p-1)~=~fracn(n+1)(n+2)...(n+p) p+1 $$



            First of all this given sum can be simplified by using factorials



            $$frac(n+p)!(n-1)!~=~n(n+1)(n+2)cdots(n+p)$$



            In general the term



            $$(x,n)~=~x^overlinen~=~frac(x+n+1)!(x+1)!$$
            is called Pochhammer symbol or rising factorial.
            $$beginalignsum_k=1^n frac(k+p-1)!(k-1)!~&=~fracn(n+1)(n+2)...(n+p) p+1\~&=~frac(n+p)!(n-1)!(p+1)endalign$$
            $$beginalignsum_k=1^n+1 frac(k+p-1)!(k-1)!~&=~frac(n+1)(n+2)(n+3)...(n+p+1) p+1\~&=~frac(n+p+1)!n!(p+1)endalign$$
            $$beginalignsum_k=1^n+1 frac(k+p-1)!(k-1)!~=~&sum_k=1^n frac(k+p-1)!(k-1)!~+~frac(n+p)n!endalign$$
            $$beginalignsum_k=1^n frac(k+p-1)!(k-1)!~+~frac(n+p)!n!~&=~frac(n+p)!(n-1)!(p+1)~+~frac(n+p)!n!\&=~fracn(n+p)!+(p+1)(n+p)!n!(p+1)\&=~frac(n+p+1)(n+p)!n!(p+1)\&=~frac(n+p+1)!n!(p+1)endalign$$



            Maybe this slightly different approach to your problem can help you to get further.






            share|cite|improve this answer















            $$sum_k=1^n k(k+1)(k+2)...(k+p-1)~=~fracn(n+1)(n+2)...(n+p) p+1 $$



            First of all this given sum can be simplified by using factorials



            $$frac(n+p)!(n-1)!~=~n(n+1)(n+2)cdots(n+p)$$



            In general the term



            $$(x,n)~=~x^overlinen~=~frac(x+n+1)!(x+1)!$$
            is called Pochhammer symbol or rising factorial.
            $$beginalignsum_k=1^n frac(k+p-1)!(k-1)!~&=~fracn(n+1)(n+2)...(n+p) p+1\~&=~frac(n+p)!(n-1)!(p+1)endalign$$
            $$beginalignsum_k=1^n+1 frac(k+p-1)!(k-1)!~&=~frac(n+1)(n+2)(n+3)...(n+p+1) p+1\~&=~frac(n+p+1)!n!(p+1)endalign$$
            $$beginalignsum_k=1^n+1 frac(k+p-1)!(k-1)!~=~&sum_k=1^n frac(k+p-1)!(k-1)!~+~frac(n+p)n!endalign$$
            $$beginalignsum_k=1^n frac(k+p-1)!(k-1)!~+~frac(n+p)!n!~&=~frac(n+p)!(n-1)!(p+1)~+~frac(n+p)!n!\&=~fracn(n+p)!+(p+1)(n+p)!n!(p+1)\&=~frac(n+p+1)(n+p)!n!(p+1)\&=~frac(n+p+1)!n!(p+1)endalign$$



            Maybe this slightly different approach to your problem can help you to get further.







            share|cite|improve this answer















            share|cite|improve this answer



            share|cite|improve this answer








            edited Jul 21 at 18:18


























            answered Jul 21 at 18:12









            mrtaurho

            700219




            700219











            • Do u mind explaining why when u multiply n! to (n+p)! why it renders to n(n+p)!
              – stevie lol
              Jul 21 at 18:50











            • I never multiplied $(n+p)!$ ny $n!$. I used the fact that $n!=n(n-1)!$. While the final denominator of the fraction is $n!(p+1)$ I have to multiply the first fraction by $fracnn$ and the second one by $fracp+1p+1$.
              – mrtaurho
              Jul 21 at 18:53










            • Sry for asking a stupid question, but how did u get rid (n-1)! from the denominator and render it to n!(p+1)?
              – stevie lol
              Jul 21 at 19:06










            • There is no problem in further asking :) $Big |$$frac(n+p)!(n-1)!(p+1)fracnn~=~fracn(n+p)!n(n-1)!(p+1)$ which is equal to $fracn(n+p)!n!(p+1)$ by the functional equation of the factorial $n!~=~n(n-1)!$
              – mrtaurho
              Jul 21 at 19:09

















            • Do u mind explaining why when u multiply n! to (n+p)! why it renders to n(n+p)!
              – stevie lol
              Jul 21 at 18:50











            • I never multiplied $(n+p)!$ ny $n!$. I used the fact that $n!=n(n-1)!$. While the final denominator of the fraction is $n!(p+1)$ I have to multiply the first fraction by $fracnn$ and the second one by $fracp+1p+1$.
              – mrtaurho
              Jul 21 at 18:53










            • Sry for asking a stupid question, but how did u get rid (n-1)! from the denominator and render it to n!(p+1)?
              – stevie lol
              Jul 21 at 19:06










            • There is no problem in further asking :) $Big |$$frac(n+p)!(n-1)!(p+1)fracnn~=~fracn(n+p)!n(n-1)!(p+1)$ which is equal to $fracn(n+p)!n!(p+1)$ by the functional equation of the factorial $n!~=~n(n-1)!$
              – mrtaurho
              Jul 21 at 19:09
















            Do u mind explaining why when u multiply n! to (n+p)! why it renders to n(n+p)!
            – stevie lol
            Jul 21 at 18:50





            Do u mind explaining why when u multiply n! to (n+p)! why it renders to n(n+p)!
            – stevie lol
            Jul 21 at 18:50













            I never multiplied $(n+p)!$ ny $n!$. I used the fact that $n!=n(n-1)!$. While the final denominator of the fraction is $n!(p+1)$ I have to multiply the first fraction by $fracnn$ and the second one by $fracp+1p+1$.
            – mrtaurho
            Jul 21 at 18:53




            I never multiplied $(n+p)!$ ny $n!$. I used the fact that $n!=n(n-1)!$. While the final denominator of the fraction is $n!(p+1)$ I have to multiply the first fraction by $fracnn$ and the second one by $fracp+1p+1$.
            – mrtaurho
            Jul 21 at 18:53












            Sry for asking a stupid question, but how did u get rid (n-1)! from the denominator and render it to n!(p+1)?
            – stevie lol
            Jul 21 at 19:06




            Sry for asking a stupid question, but how did u get rid (n-1)! from the denominator and render it to n!(p+1)?
            – stevie lol
            Jul 21 at 19:06












            There is no problem in further asking :) $Big |$$frac(n+p)!(n-1)!(p+1)fracnn~=~fracn(n+p)!n(n-1)!(p+1)$ which is equal to $fracn(n+p)!n!(p+1)$ by the functional equation of the factorial $n!~=~n(n-1)!$
            – mrtaurho
            Jul 21 at 19:09





            There is no problem in further asking :) $Big |$$frac(n+p)!(n-1)!(p+1)fracnn~=~fracn(n+p)!n(n-1)!(p+1)$ which is equal to $fracn(n+p)!n!(p+1)$ by the functional equation of the factorial $n!~=~n(n-1)!$
            – mrtaurho
            Jul 21 at 19:09











            up vote
            0
            down vote













            I'm not sure how or why you are writing 1).



            Just do the following.



            Assuming that $sum_k=1^n k(k+1)(k+2)...(k+p-1)= fracn(n+1)(n+2)...(n+p) p+1$



            Then $sum_k=1^n+1k(k+1)...(k+p-1) = [sum_k=1^n k(k+1)...(k+p-1)]+ (n+1)((n+1)+1)...((n+1)+p-1)$



            $= fracn(n+1)...(n+p) p+1 + (n+1)(n+2)....(n+p-1)(n+p)$



            $= [(n+1)(n+2).....(n+p)](frac np+1 + 1)$



            $=[(n+1)(n+2).....(n+p)](frac np+1 + fracp+1p+1)$



            $=[(n+1)(n+2).....(n+p)](frac n+p + 1p+1)$



            $=frac (n+1).....(n+1 + p)p+1$






            share|cite|improve this answer

























              up vote
              0
              down vote













              I'm not sure how or why you are writing 1).



              Just do the following.



              Assuming that $sum_k=1^n k(k+1)(k+2)...(k+p-1)= fracn(n+1)(n+2)...(n+p) p+1$



              Then $sum_k=1^n+1k(k+1)...(k+p-1) = [sum_k=1^n k(k+1)...(k+p-1)]+ (n+1)((n+1)+1)...((n+1)+p-1)$



              $= fracn(n+1)...(n+p) p+1 + (n+1)(n+2)....(n+p-1)(n+p)$



              $= [(n+1)(n+2).....(n+p)](frac np+1 + 1)$



              $=[(n+1)(n+2).....(n+p)](frac np+1 + fracp+1p+1)$



              $=[(n+1)(n+2).....(n+p)](frac n+p + 1p+1)$



              $=frac (n+1).....(n+1 + p)p+1$






              share|cite|improve this answer























                up vote
                0
                down vote










                up vote
                0
                down vote









                I'm not sure how or why you are writing 1).



                Just do the following.



                Assuming that $sum_k=1^n k(k+1)(k+2)...(k+p-1)= fracn(n+1)(n+2)...(n+p) p+1$



                Then $sum_k=1^n+1k(k+1)...(k+p-1) = [sum_k=1^n k(k+1)...(k+p-1)]+ (n+1)((n+1)+1)...((n+1)+p-1)$



                $= fracn(n+1)...(n+p) p+1 + (n+1)(n+2)....(n+p-1)(n+p)$



                $= [(n+1)(n+2).....(n+p)](frac np+1 + 1)$



                $=[(n+1)(n+2).....(n+p)](frac np+1 + fracp+1p+1)$



                $=[(n+1)(n+2).....(n+p)](frac n+p + 1p+1)$



                $=frac (n+1).....(n+1 + p)p+1$






                share|cite|improve this answer













                I'm not sure how or why you are writing 1).



                Just do the following.



                Assuming that $sum_k=1^n k(k+1)(k+2)...(k+p-1)= fracn(n+1)(n+2)...(n+p) p+1$



                Then $sum_k=1^n+1k(k+1)...(k+p-1) = [sum_k=1^n k(k+1)...(k+p-1)]+ (n+1)((n+1)+1)...((n+1)+p-1)$



                $= fracn(n+1)...(n+p) p+1 + (n+1)(n+2)....(n+p-1)(n+p)$



                $= [(n+1)(n+2).....(n+p)](frac np+1 + 1)$



                $=[(n+1)(n+2).....(n+p)](frac np+1 + fracp+1p+1)$



                $=[(n+1)(n+2).....(n+p)](frac n+p + 1p+1)$



                $=frac (n+1).....(n+1 + p)p+1$







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                answered Jul 21 at 19:05









                fleablood

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