Proving this binomial identity

In summary, the conversation revolved around understanding and proving the identity \sum_{m=k}^{n-k}\binom{m}{k}\binom{n-m}{k}=\binom{n+1}{2k+1}. The person speaking mentioned that they were able to understand the combinatorial proof of the identity, but were unsure of how to prove it themselves. They also mentioned that they did not understand how the binomial was manipulated in the proof. Another person suggested using the example of a bag of balls to understand the reasoning behind the identity, but the first person did not find this explanation helpful. Overall, the identity remained a frustrating concept for the first person.
  • #1
chaotixmonjuish
287
0
[tex]\sum_{m=k}^{n-k}\binom{m}{k}\binom{n-m}{k}=\binom{n+1}{2k+1}[/tex]


I'm not sure how to prove it, I understand the combinatorial proof..i.e. putting it to an example...but i can't derive one side and get the other.
 
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  • #2
How do you understand the combinatorial proof but not know how to prove it?
 
  • #3
It was an example given in the book. I just don't see how they manipulated the binomial to move the stuff around.
 
  • #4
Suppose you had a bag full of n balls. Suppose out of the n balls you had m green ones. Would the right hand side be adding up the ways to count all the gree balls and non-green balls. I didn't even really understand this reasoning. This identity is really frustrating me.
 

FAQ: Proving this binomial identity

What is a binomial identity?

A binomial identity is an algebraic equation that relates two binomial expressions. It is also known as a binomial theorem and is used to expand the powers of a binomial expression.

How do you prove a binomial identity?

To prove a binomial identity, you need to use mathematical properties and techniques such as the distributive property, the binomial theorem, and algebraic manipulation. You can also use mathematical induction to prove binomial identities.

What are some common binomial identities?

Some common binomial identities include the binomial theorem, Pascal's triangle, and the binomial coefficients. These identities are often used in algebra, calculus, and other branches of mathematics.

Why is it important to prove binomial identities?

Proving binomial identities is important because it helps to strengthen our understanding of algebraic concepts and techniques. It also allows us to solve more complex mathematical problems and derive new equations and formulas.

What are some tips for proving binomial identities?

Some tips for proving binomial identities include familiarizing yourself with the properties and theorems related to binomial expressions, breaking down the identity into smaller, more manageable parts, and practicing with various examples and exercises. It is also helpful to check your work and make sure each step is logically sound.

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