Summation with Binomial Expansion

In summary, the given relationship can be proven using the binomial theorem and simplifying the resulting hypergeometric functions. The correct notation for the binomial coefficient is also provided.
  • #1
Jake1802
8
0

Homework Statement


How can i prove this relationship
\sum _{i=0}^k \text{Binomial}[n+1,k-2i] - \sum _{i=0}^k \text{Binomial}[n,k-2i]=\sum _{i=0}^k \text{Binomial}[n,k-1-2i]

Homework Equations


Binomial (n,k)=n^k/k!

The Attempt at a Solution



I attempted subbing into mathyematica but this didn't work so i attempted by hand and got completely lost. Any helpful comments would be helpful.
Result from Mathematica
-Binomial[n, -1 + k] HypergeometricPFQ[{1, 1/2 - k/2,
1 - k/2}, {1 - k/2 + n/2, 3/2 - k/2 + n/2}, 1] -
Binomial[n,
k] HypergeometricPFQ[{1, 1/2 - k/2, -(k/2)}, {1/2 - k/2 + n/2,
1 - k/2 + n/2}, 1] +
Binomial[1 + n,
k] HypergeometricPFQ[{1, 1/2 - k/2, -(k/2)}, {1 - k/2 + n/2,
3/2 - k/2 + n/2}, 1]
 
Last edited:
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  • #2
Fixed your LaTex. Is this the relation you're supposed to prove?

[tex]\sum_{i=0}^k \begin{pmatrix}n+1\\k-2i\end{pmatrix} - \sum_{i=0}^k \begin{pmatrix}n\\k-2i\end{pmatrix}=\sum_{i=0}^k \begin{pmatrix}n\\k-1-2i\end{pmatrix}[/tex]

I don't think it's correct because k-2i<0 for some values of i in the summation.

Binomial (n,k)=n^k/k!
That's not right. It should be

[tex]\begin{pmatrix}n\\k\end{pmatrix}=\frac{n!}{k!(n-k)!}[/tex]
 
  • #3
but when k-2i<0 the value will be zero
 

Related to Summation with Binomial Expansion

1. What is the formula for summation with binomial expansion?

The formula for summation with binomial expansion is (a + b)^n = ∑(k = 0 to n) (n choose k) * a^(n-k) * b^k, where n is the power, a and b are constants, and (n choose k) is the binomial coefficient.

2. How do you calculate the binomial coefficient?

The binomial coefficient, also known as the combination, is calculated using the formula (n choose k) = n! / (k! * (n-k)!), where n is the total number of items and k is the number of items chosen.

3. What is the purpose of using binomial expansion in summation?

The purpose of using binomial expansion in summation is to simplify and express complex polynomial expressions, making it easier to calculate the values of large powers.

4. Can binomial expansion be used for non-integer powers?

Yes, binomial expansion can be used for non-integer powers. The formula for this is (a + b)^x = ∑(k = 0 to ∞) (x choose k) * a^(x-k) * b^k, where (x choose k) is calculated using the binomial theorem for non-integer powers.

5. How is binomial expansion related to Pascal's triangle?

Binomial expansion is closely related to Pascal's triangle, as the coefficients in the expansion can be found by reading the corresponding row in Pascal's triangle. The first term in the expansion corresponds to the first number in the row, the second term corresponds to the second number, and so on.

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