Generating functions with n term outside

In summary, The conversation discusses the possibility of having a generating function with an n term outside the sum. The example given is 2^n * SUM (b_n(0.5)^n * z^n), where the first term would be 2^n * b_0 * z^0. The speaker also mentions having the closed formula for b_n. However, they clarify that if the sum is over the index n, it would be bad notation and could easily be confused with another notation. They suggest using a different index, such as i, for clarity.
  • #1
SpartanG345
70
1

Homework Statement



Discrete mathematics

is it possible to have a generating function where there is an n term outside the sum?

such as

2^n SUM ( bn(0.5)^n * z^n)

eg the 1st turn would be 2^n bo z^0

when you evaluate the series it evaluates to the series which i am trying to create a generating function for. NB bn is another generating function.

I also have the closed formula for bn.
 
Physics news on Phys.org
  • #2
Assuming the sum itself is over the index n, that would be bad notation. It means the same as [itex]2^n \sum_k (b_k(0.5)^k z^k)[/itex] but NOT the same as [itex]\sum_n 2^n(b_n(0.5)^n z^n)[/itex] with which it could easily be confused. On the other hand if the sum is over, say, index i from 0 to n, it would be perfectly good.
 

FAQ: Generating functions with n term outside

What is a generating function with n term outside?

A generating function with n term outside is a mathematical tool used to represent a sequence of numbers or coefficients in a compact and systematic way. It is typically written in the form of a power series, where the n-th term is multiplied by a variable x^n. This allows for the efficient calculation of sums and products involving the sequence.

How is a generating function with n term outside different from a regular generating function?

A regular generating function is typically written in the form of a power series, where each term is multiplied by a variable x^n. However, a generating function with n term outside has an additional factor of n in the n-th term. This extra factor allows for more complex calculations to be performed, such as finding the coefficients of a product of two sequences.

What are the practical applications of generating functions with n term outside?

Generating functions with n term outside are commonly used in combinatorics and number theory, as well as in other areas of mathematics and science. They can be used to solve problems related to counting, probability, and optimization. In physics, generating functions with n term outside can be used to model and analyze systems with discrete energy levels.

How can one construct a generating function with n term outside?

To construct a generating function with n term outside, one typically starts with a regular generating function and manipulates it algebraically. This can involve using identities, such as the binomial theorem or the Cauchy product formula, to transform the series into a form with the desired term outside. Alternatively, one can use generating function software or programming languages to generate the series automatically.

Are there any limitations to using generating functions with n term outside?

Like any mathematical tool, generating functions with n term outside have their limitations. They may not be applicable to all types of sequences or problems, and their use may require a strong understanding of power series and algebraic manipulation. In addition, the resulting series may not always have a closed form expression, making it difficult to calculate specific terms or coefficients.

Similar threads

Back
Top