# Recent content by Hoplite

1. ### A tricky inverse Laplace transform

Oh yeah, I didn't look closely enough at that function. That inverse Laplace transform I posted does work too though, which is odd. I guess it's probably just a rearranged form of the other inverse Laplace transform though.

8. ### A scalar on a semi-infinite domain with source and sink

Hi Orodruin, thanks for your response. Yes, it's not the heat equation. I just mentioned heat as an example of a possible scalar quantity. I can see no reason why the time derivative couldn't be removed from the heat equation if the system is assumed to be steady state though. As for sink...
9. ### A scalar on a semi-infinite domain with source and sink

Hi everyone, I've been looking at a problem that seems simple at first, but appears to be deceptively difficult (unless I'm missing something). 1. Homework Statement I've been looking at a problem that involves the diffusion of a scalar quantity, ##q(x)##, on the semi-infinite domain, ##\leq...
10. ### Looking for a modified Poisson distribution

I'm looking to model a system in which events are nearly perfectly randomly distributed but with a slight tendency for events to avoid each other. As you know, if the system were perfectly random, I could use a Poisson distribution. The probability distribution for the number of events would...
11. ### Approximating unsolvable recursion relations

That's correct. In fact my equation is S''''+(a+bx^2)S''+(c+dx^2)S=0, with some inhomogenious boundary conditions.
12. ### Approximating unsolvable recursion relations

Oops, sorry. I had the wrong equation for S. I've fixed it now.
13. ### Approximating unsolvable recursion relations

I have a complicated recursion replation, which I'm sure is unsolvable. (By "unsolvable" I mean that there is no closed form solution expressing \xi_1, \xi_2, \xi_3, etc. in terms of \xi_0.) It goes \frac{(k+4)!}{k!}\xi_{k+4} +K_1 (k+2)(k+1)\xi_{k+2}+ [ K_2 k(k-1) +K_3] \xi_{k} +K_4...
14. ### Why doesn't this method work? (Re: Simultaneous ODEs)

Yes, that's what I've done.
15. ### Why doesn't this method work? (Re: Simultaneous ODEs)

I have been working on a derivation in which the following simultateous ordinary differential equations have appeared: f^{(4)}(x)-2 a^2 f''(x)+a^4 f(x)+b(g''(x)-a^2 g(x))=0, g^{(4)}(x)-2 a^2 g''(x)+a^4 g(x)-b(f''(x)-a^2 f(x))=0, where a and b are constants. I figured that I could solve...