## New answers tagged special-functions

2
votes

### Integrating $\int_0^\infty \sqrt x e^{-4/3x^{3/2}}\left(\int_0^x \operatorname{Ai}(t)dt\int_0^x \operatorname{Bi}(t)dt\right)dx$

$
\DeclareMathOperator{\Ai}{\mathrm{Ai}}
\DeclareMathOperator{\Bi}{\mathrm{Bi}}
$This is not a full answer (yet). As commented by @Timothy, the problem can be rewritten using modified Bessel functions ...

- 1,844

3
votes

### What are the properties of umbra with moments $\{1,1/2,1/3,1/4,1/5,...\}$?

I'll sketch here some of the general Sheffer Appell-umbral calculus relationships between the Bernoulli numbers / polynomials and the reciprocal (natural) numbers / polynomials. Perhaps when I have ...

- 8,601

2
votes

Accepted

### Sum over Bessel functions: what is $\sum_{n=1}^\infty J_n(u)J_n(v)\sin(n\alpha)$?

I don't think a "closed form" expression exists, I tried several approaches. I guess the best one can do is to use a modified version of the OP's integral representation.
Denote
$$
w(\psi) = ...

- 1,844

3
votes

### Sum over Bessel functions: what is $\sum_{n=1}^\infty J_n(u)J_n(v)\sin(n\alpha)$?

Comment
"Neumann's addition theorem"
A special case of Gradshteyn & Ryzhik 8.530.2 is
$$
{{ J}_{0}\left(m\sqrt {{r}^{2}+{\rho}^{2}-2\,r\rho\,\cos \left(
\phi \right) }\right)}=\sum _{k=-...

- 38.8k

2
votes

Accepted

### Where or what is the general formula for the $n$th derivative of the power-exponential function $x^x$?

The Stirling numbers of the first kind $s(n,k)$ for $n\ge k\ge0$ can be analytically generated by
\begin{equation*}%\label{1st-stirl-gen-funct}
\frac{[\ln(1+t)]^k}{k!}=\sum_{n=k}^\infty s(n,k)\frac{t^...

- 584

4
votes

Accepted

### Identity involving Stirling number of the second kind

The first formula in Section 24.1.4.I.B in Handbook of mathematical functions with formulas, graphs, and mathematical tables, Dover edition, 1965 (Library of Congress Catalog Card Number: 65.12253) by ...

- 90.3k

2
votes

Accepted

### Solutions of complex linear difference equations

Look for a solution of the form $f(z)=e^{\lambda z}$. Plugging this to your equation, you obtain that
$\lambda$ must be a zero of the entire function
$$F(\lambda)=\sum_{j=1}^n e^{\lambda\eta_j}.$$
...

- 83.2k

5
votes

Accepted

### Asymptotic analysis of an expression involving a Fox's H function

Your expression can be simplified as follows: As $m=q=4$, the denominator parameter $(0,1)$ cancels with the numerator parameter $(0,1)$. Furthermore, as all linear coefficients are one, the Fox H ...

- 66

0
votes

### The exact constant in a bound on ratios of Gamma functions

The optimal $C$ is $\mathrm{e}$.
Proof:
We have
$$\ln C \ge \ln a - \ln(a + b)
+ \frac{\ln \Gamma(a + b)
-\ln a - \ln\Gamma(a) - \ln\Gamma(b)}{a}.$$
Let
$$F(a, b) := \ln a - \ln(a + b)
+ \frac{\ln ...

- 733

3
votes

Accepted

### Definite integral of the square root of a polynomial ratio

The expression obtained by @Robert can be simplified with the Imaginary-Argument Transformation from DLMF 19.7.7. Then, the limit $t\to 1^-$ can be performed. The result can be further simplified and ...

- 1,844

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