Why $sum_i = j^inftyfraci!(i-j)!cdot j!cdot k^i-jcdot (1-k)^j = 1/(1-k)$? The Next CEO of Stack Overflowmaybe this sum have approximation $sum_k=0^nbinomnk^3approxfrac2pisqrt3ncdot 8^n,ntoinfty$How prove binomial cofficients $sum_k=0^[fracn3](-1)^kbinomn+1kbinom2n-3kn=sum_k=[fracn2]^nbinomn+1kbinomkn-k$How find the sum $2sum_k=1^inftysum_i=0^2k-1fracbinom2kicdot B_icdot(m-1)^2k-i2k(2k-1)m^2k-1$How to prove that $sum_k=0^infty binomxx-kcdotbinomxk-x = 1$?prove that $(frac16)^4cdotlim_nrightarrowinftysum_i=4^nbinomi-13(frac56)^i-4=1$Evaluate$sum_n=0^inftybinom3nnx^n$$sum_i=1^ni^k=sum_i=1^kfracc_k+1-ik!i!n^i$. What is known about $c_k_k=0^infty$?$lim_limitssigma_A, sigma_B to infty e^-sigma_A-sigma_B sum_k=0^infty fracsigma_A^kk!cdotfracsigma_B^k+1(k+1)!$Proof for binomial theorem $ (1+x)^a = sum_k=0^infty P_k(a)x^k $Help understanding proof of the following statement $E(Y) = sum_i = 1^infty P(Y geq k)$

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Why $sum_i = j^inftyfraci!(i-j)!cdot j!cdot k^i-jcdot (1-k)^j = 1/(1-k)$?



The Next CEO of Stack Overflowmaybe this sum have approximation $sum_k=0^nbinomnk^3approxfrac2pisqrt3ncdot 8^n,ntoinfty$How prove binomial cofficients $sum_k=0^[fracn3](-1)^kbinomn+1kbinom2n-3kn=sum_k=[fracn2]^nbinomn+1kbinomkn-k$How find the sum $2sum_k=1^inftysum_i=0^2k-1fracbinom2kicdot B_icdot(m-1)^2k-i2k(2k-1)m^2k-1$How to prove that $sum_k=0^infty binomxx-kcdotbinomxk-x = 1$?prove that $(frac16)^4cdotlim_nrightarrowinftysum_i=4^nbinomi-13(frac56)^i-4=1$Evaluate$sum_n=0^inftybinom3nnx^n$$sum_i=1^ni^k=sum_i=1^kfracc_k+1-ik!i!n^i$. What is known about $c_k_k=0^infty$?$lim_limitssigma_A, sigma_B to infty e^-sigma_A-sigma_B sum_k=0^infty fracsigma_A^kk!cdotfracsigma_B^k+1(k+1)!$Proof for binomial theorem $ (1+x)^a = sum_k=0^infty P_k(a)x^k $Help understanding proof of the following statement $E(Y) = sum_i = 1^infty P(Y geq k)$










1












$begingroup$


$$
sum_i = j^inftyfraci!(i-j)!cdot j!cdot k^i-jcdot (1-k)^j = frac11-k
$$

I take this equal than I do some problem of probabiliti teory. I think that it will be prove by indukcia, but I can't.










share|cite|improve this question











$endgroup$











  • $begingroup$
    I have edited your expression using MathJax. Could you please check it to see if I did any mistakes. And for next time, consider using it yourself; it makes formulas much easier to read.
    $endgroup$
    – Arthur
    Mar 18 at 12:57










  • $begingroup$
    Sorry, I forgot to say that k is probability. So it is 0<k<1.
    $endgroup$
    – Andrey Komisarov
    Mar 18 at 13:00










  • $begingroup$
    @AndreyKomisarov It is not clear what you mean. Please check if it is the following one: $sum_i=1^infty sum_j=i^infty i choose jcdot k^i-jcdot (1-k)^j$.
    $endgroup$
    – callculus
    Mar 18 at 15:56











  • $begingroup$
    @callculus No, j is a constant, the suming is only by i.
    $endgroup$
    – Andrey Komisarov
    Mar 18 at 19:40















1












$begingroup$


$$
sum_i = j^inftyfraci!(i-j)!cdot j!cdot k^i-jcdot (1-k)^j = frac11-k
$$

I take this equal than I do some problem of probabiliti teory. I think that it will be prove by indukcia, but I can't.










share|cite|improve this question











$endgroup$











  • $begingroup$
    I have edited your expression using MathJax. Could you please check it to see if I did any mistakes. And for next time, consider using it yourself; it makes formulas much easier to read.
    $endgroup$
    – Arthur
    Mar 18 at 12:57










  • $begingroup$
    Sorry, I forgot to say that k is probability. So it is 0<k<1.
    $endgroup$
    – Andrey Komisarov
    Mar 18 at 13:00










  • $begingroup$
    @AndreyKomisarov It is not clear what you mean. Please check if it is the following one: $sum_i=1^infty sum_j=i^infty i choose jcdot k^i-jcdot (1-k)^j$.
    $endgroup$
    – callculus
    Mar 18 at 15:56











  • $begingroup$
    @callculus No, j is a constant, the suming is only by i.
    $endgroup$
    – Andrey Komisarov
    Mar 18 at 19:40













1












1








1





$begingroup$


$$
sum_i = j^inftyfraci!(i-j)!cdot j!cdot k^i-jcdot (1-k)^j = frac11-k
$$

I take this equal than I do some problem of probabiliti teory. I think that it will be prove by indukcia, but I can't.










share|cite|improve this question











$endgroup$




$$
sum_i = j^inftyfraci!(i-j)!cdot j!cdot k^i-jcdot (1-k)^j = frac11-k
$$

I take this equal than I do some problem of probabiliti teory. I think that it will be prove by indukcia, but I can't.







probability binomial-coefficients






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Mar 18 at 12:56









Arthur

120k7121206




120k7121206










asked Mar 18 at 12:53









Andrey KomisarovAndrey Komisarov

726




726











  • $begingroup$
    I have edited your expression using MathJax. Could you please check it to see if I did any mistakes. And for next time, consider using it yourself; it makes formulas much easier to read.
    $endgroup$
    – Arthur
    Mar 18 at 12:57










  • $begingroup$
    Sorry, I forgot to say that k is probability. So it is 0<k<1.
    $endgroup$
    – Andrey Komisarov
    Mar 18 at 13:00










  • $begingroup$
    @AndreyKomisarov It is not clear what you mean. Please check if it is the following one: $sum_i=1^infty sum_j=i^infty i choose jcdot k^i-jcdot (1-k)^j$.
    $endgroup$
    – callculus
    Mar 18 at 15:56











  • $begingroup$
    @callculus No, j is a constant, the suming is only by i.
    $endgroup$
    – Andrey Komisarov
    Mar 18 at 19:40
















  • $begingroup$
    I have edited your expression using MathJax. Could you please check it to see if I did any mistakes. And for next time, consider using it yourself; it makes formulas much easier to read.
    $endgroup$
    – Arthur
    Mar 18 at 12:57










  • $begingroup$
    Sorry, I forgot to say that k is probability. So it is 0<k<1.
    $endgroup$
    – Andrey Komisarov
    Mar 18 at 13:00










  • $begingroup$
    @AndreyKomisarov It is not clear what you mean. Please check if it is the following one: $sum_i=1^infty sum_j=i^infty i choose jcdot k^i-jcdot (1-k)^j$.
    $endgroup$
    – callculus
    Mar 18 at 15:56











  • $begingroup$
    @callculus No, j is a constant, the suming is only by i.
    $endgroup$
    – Andrey Komisarov
    Mar 18 at 19:40















$begingroup$
I have edited your expression using MathJax. Could you please check it to see if I did any mistakes. And for next time, consider using it yourself; it makes formulas much easier to read.
$endgroup$
– Arthur
Mar 18 at 12:57




$begingroup$
I have edited your expression using MathJax. Could you please check it to see if I did any mistakes. And for next time, consider using it yourself; it makes formulas much easier to read.
$endgroup$
– Arthur
Mar 18 at 12:57












$begingroup$
Sorry, I forgot to say that k is probability. So it is 0<k<1.
$endgroup$
– Andrey Komisarov
Mar 18 at 13:00




$begingroup$
Sorry, I forgot to say that k is probability. So it is 0<k<1.
$endgroup$
– Andrey Komisarov
Mar 18 at 13:00












$begingroup$
@AndreyKomisarov It is not clear what you mean. Please check if it is the following one: $sum_i=1^infty sum_j=i^infty i choose jcdot k^i-jcdot (1-k)^j$.
$endgroup$
– callculus
Mar 18 at 15:56





$begingroup$
@AndreyKomisarov It is not clear what you mean. Please check if it is the following one: $sum_i=1^infty sum_j=i^infty i choose jcdot k^i-jcdot (1-k)^j$.
$endgroup$
– callculus
Mar 18 at 15:56













$begingroup$
@callculus No, j is a constant, the suming is only by i.
$endgroup$
– Andrey Komisarov
Mar 18 at 19:40




$begingroup$
@callculus No, j is a constant, the suming is only by i.
$endgroup$
– Andrey Komisarov
Mar 18 at 19:40










1 Answer
1






active

oldest

votes


















0












$begingroup$

it helps to write $i=j+l$, then divide out $(1-k)^j$ to restate the claim as $sum_lge 0binomj+ljk^l=(1-k)^-j-1$. This is just a special case of the binomial theorem, since the falling Pochhammer symbol $(-j-1)_l=binomj+lj(-1)^l$.






share|cite|improve this answer









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    1 Answer
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    active

    oldest

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    0












    $begingroup$

    it helps to write $i=j+l$, then divide out $(1-k)^j$ to restate the claim as $sum_lge 0binomj+ljk^l=(1-k)^-j-1$. This is just a special case of the binomial theorem, since the falling Pochhammer symbol $(-j-1)_l=binomj+lj(-1)^l$.






    share|cite|improve this answer









    $endgroup$

















      0












      $begingroup$

      it helps to write $i=j+l$, then divide out $(1-k)^j$ to restate the claim as $sum_lge 0binomj+ljk^l=(1-k)^-j-1$. This is just a special case of the binomial theorem, since the falling Pochhammer symbol $(-j-1)_l=binomj+lj(-1)^l$.






      share|cite|improve this answer









      $endgroup$















        0












        0








        0





        $begingroup$

        it helps to write $i=j+l$, then divide out $(1-k)^j$ to restate the claim as $sum_lge 0binomj+ljk^l=(1-k)^-j-1$. This is just a special case of the binomial theorem, since the falling Pochhammer symbol $(-j-1)_l=binomj+lj(-1)^l$.






        share|cite|improve this answer









        $endgroup$



        it helps to write $i=j+l$, then divide out $(1-k)^j$ to restate the claim as $sum_lge 0binomj+ljk^l=(1-k)^-j-1$. This is just a special case of the binomial theorem, since the falling Pochhammer symbol $(-j-1)_l=binomj+lj(-1)^l$.







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Mar 18 at 13:00









        J.G.J.G.

        32.3k23250




        32.3k23250



























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