Do we have a general solution infinite series for the gamma function?

In summary, there are two general solutions for the gamma function: one using Laguerre polynomials and another using Taylor series. The first solution has restrictions on the input while the second one is limited to values within the range of (z-1)<1. However, there is also a third solution using the reciprocal gamma function, which is an entire function and has coefficients given in Wikipedia's article. There may be other general solutions, but they have not been mentioned.
  • #1
mesa
Gold Member
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Does anyone know if we currently have an infinite series summation general solution for the gamma function such as,


$$\frac{1}{\Gamma(k)}=\sum_{n=0}^{\infty} f(n,k)$$

or,

$${\Gamma(k)}=\sum_{n=0}^{\infty} f(n,k)$$?
 
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  • #3
mathman said:

How I miss these things in wikipedia I will never know...
Okay I see the following two general solutions,

$$\Gamma(t)=x^t \sum_{n=0}^{\infty} \frac{L_n^{(t)}(x)}{t+n}$$

$$\Gamma(z) = 1+\sum_{k=1}^\infty\frac{\Gamma^{(k)}(1)}{k!}(z-1)^{k}$$

For the first one I am unfamiliar with Laguerre polynomials. Does this cause any restrictions on the input of the function?

The second one only works for the absolute value of (z-1)<1 so it is pretty limited.

Are there any others?
 
  • #4
Well I have something much better, if anyone knows of anything else please respond.
 
  • #5
[itex]1/\Gamma[/itex] is an entire function, so its Taylor series converges to it everywhere. The coefficients are given at Wikipedia's article on the reciprocal gamma function.
 
  • #6
eigenperson said:
[itex]1/\Gamma[/itex] is an entire function, so its Taylor series converges to it everywhere. The coefficients are given at Wikipedia's article on the reciprocal gamma function.

Are you referring to the Taylor series as another general solution except in the form of [itex]1/\Gamma[/itex]?
 
  • #7
Update, my function now also works for imaginary values in addition to the real number line.
 

1. What is the gamma function and why is it important in mathematics?

The gamma function is a mathematical function that extends the concept of factorial to real and complex numbers. It is important in many areas of mathematics, including number theory, statistics, and physics, as it allows for the calculation of integrals and infinite series involving factorials.

2. Is there a general solution for infinite series involving the gamma function?

No, there is no general solution for infinite series involving the gamma function. While some special cases may have closed-form solutions, in general, infinite series involving the gamma function can only be approximated using numerical methods.

3. Can the gamma function be written in terms of elementary functions?

No, the gamma function cannot be written in terms of elementary functions. It is a special function that cannot be expressed using a finite combination of basic arithmetic operations, exponentials, logarithms, or trigonometric functions.

4. What techniques are used to approximate infinite series involving the gamma function?

The most commonly used techniques to approximate infinite series involving the gamma function are numerical integration and asymptotic expansions. These methods involve breaking down the series into smaller parts and then using numerical algorithms or known approximations to calculate each part separately.

5. Are there any open problems or unsolved mysteries related to the gamma function?

Yes, there are still many open problems and unsolved mysteries related to the gamma function. One of the most well-known is the Riemann hypothesis, which states that all nontrivial zeros of the Riemann zeta function, a related function to the gamma function, lie on the critical line. Additionally, there are ongoing efforts to find more efficient and accurate methods for approximating infinite series involving the gamma function.

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