Science Fair Projects Ideas - Talk:Binomial coefficient

All Science Fair Projects

      

Science Fair Project Encyclopedia for Schools!

  Search    Browse    Forum  Coach    Links    Editor    Help    Tell-a-Friend    Encyclopedia    Dictionary     

Science Fair Project Encyclopedia

For information on any area of science that interests you,
enter a keyword (eg. scientific method, molecule, cloud, carbohydrate etc.).
Or else, you can start by choosing any of the categories below.

Talk:Binomial coefficient

Does anyone want to add the general binomial theorem (for all n). Also I have some weird alternative formulas for C(n,r) with n a non-negative integer, but I'd have to set up the pictures on a stable server or something.

Definition of binomial coefficients for n < 0

To Maxal and whoever else is willing to comment:

I would say that the recently inserted equation

(1+x)^n = {n\choose 0} + {n\choose 1}x + {n\choose 2}x^2 + \dots = \sum_k {n\choose k} x^k.

is reduntant, because of

(x+y)^n = \sum_{k=0}^{n} {n \choose k} x^k y^{n-k} \qquad (2)

which shows up below.

The latter formula makes sense only for integer n \geq 0. While the former one is true for any n. --Maxal 22:47, 13 Apr 2005 (UTC)
The point is, everywhere in this article it is assumed that n ≥ 0. Just read through it. The Pascal triangle for example, does not hold for n < 0. I find your addition not in the right place. I think it rather belongs in a generalization section at the end of the article. What do you think? Oleg Alexandrov 23:03, 13 Apr 2005 (UTC)
Disagree. It's the only complete definition for now. And it should come first. I think Pascal triangle and other middle-school-level stuff should form a separate section. --Maxal 23:07, 13 Apr 2005 (UTC)
Please notice that the generalization to n < 0, actually, for any n complex, is at already in the article, see several sections below in there. Oleg Alexandrov 23:10, 13 Apr 2005 (UTC)
First of all, there is a bad mixture of notations. C_n^k or C(n,k) is the number of combinations and it's defined only for non-negative integer n,k (Pascal's triangle is actually defined for C(n,k)). The binomial coefficient {n\choose k} is a generalization of C_n^k which is defined for integer k and arbitrary n. As of generalization of {n\choose k} to complex n, it's ok except for notation. C(n,k) is inappropriate.
Second, the article makes accent on combinatorics where complex n have no (or very limited) application. Hence, it's ok to keep the generalization to complex n at the end. --Maxal 23:26, 13 Apr 2005 (UTC)
So, what are the applications of negative n to combinatorics? Oleg Alexandrov 23:28, 13 Apr 2005 (UTC)
Say, they often appear in expansions of generating functions. And there many self-reverse relations including them. --Maxal 23:37, 13 Apr 2005 (UTC)

So, if you want to really make some changes to this article, you should read it all, then see how to make things look nice overall. What do you think?

I've read it all, and there was no correct definition for binomial coefficients for n<0. Moreover, in the discussion you can see a request for the definition "general" binomial coefficient. I've provided a general definition of binomial coefficients (most popular in combinatorics). From this very same expansion binomial coefficients can be also defined for non-integer n but that's mainly related to analysis. --Maxal 22:47, 13 Apr 2005 (UTC)

Also, please see the sentence:

This is generalized by the binomial theorem, which allows the exponent n to be negative or a non-integer.

in the article. Did you notice it? Oleg Alexandrov 22:42, 13 Apr 2005 (UTC)

Yes but that article should not prevent for providing correct and complete definition of the binomial coefficients. --Maxal 22:47, 13 Apr 2005 (UTC)
Last updated: 06-04-2005 17:50:46
10-26-2009 08:16:03
The contents of this article is licensed from www.wikipedia.org under the GNU Free Documentation License. Click here to see the transparent copy and copyright details
Science kits, science lessons, science toys, maths toys, hobby kits, science games and books - these are some of many products that can help give your kid an edge in their science fair projects, and develop a tremendous interest in the study of science. When shopping for a science kit or other supplies, make sure that you carefully review the features and quality of the products. Compare prices by going to several online stores. Read product reviews online or refer to magazines.

Start by looking for your science kit review or science toy review. Compare prices but remember, Price $ is not everything. Quality does matter.
Science Fair Coach
What do science fair judges look out for?
ScienceHound
Science Fair Projects for students of all ages
All Science Fair Projects.com Site
All Science Fair Projects Homepage
Search | Browse | Links | From-our-Editor | Books | Help | Contact | Privacy | Disclaimer | Copyright Notice