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Jun
18
comment How to get this numerical solution of a integro-differential equation
Why not help Mathematica out a bit and see if you can turn your integro-differential equation into an ODE?
Jun
10
comment How to make Poisson voronoi diagram
The output of RandomVariate[PoissonDistribution[(* stuff *)]] is an integer, right? That is the number of points you need to generate in the cell that number is associated with.
Jun
10
comment How to make Poisson voronoi diagram
You just cut the square into $n\times n$ smaller squares, for some $n$.
Jun
10
comment How to make Poisson voronoi diagram
The idea is relatively simple: in two dimensions, if you have a square region, split it into "cells", associate each cell with a Poisson-distributed random integer (call it $k$), and generate $k$ points in that cell with the coordinates drawn from a uniform distribution.
Jun
2
comment skewness and kurtosis - different definitions
Anyway, if you want, I can move this to the statistics SE site.
Jun
2
comment skewness and kurtosis - different definitions
We use Mathematica here, not Maple. (Maybe our site logo is not that readable?)
May
31
comment Some expectations of psi (digamma) function
It doesn't look to me that this has a closed form; you can try to derive a series by substituting in the series for the digamma function, however.
May
29
comment One point following another moving in a straight line?
I'll move this to math.SE, but to help you anyway: what you're interested in is called a pursuit curve.
May
27
comment If Q is an orthogonal matrix, does it follow that $QDQ^T = Q^TDQ$?
I really wish people would just try things out sometimes; it's not like failed experiments in mathematics will blow up in your face.
May
24
comment This one weird thing that bugs me about summation and the like
Well, Thiele expansion is the exact analog of Taylor expansion for continued fractions. In this case, instead of evaluating derivatives at your expansion point, you're evaluating reciprocal derivatives.
May
24
comment This one weird thing that bugs me about summation and the like
With respect to the continued fraction: you'll want to look up Thiele expansion and reciprocal detivatives.
May
24
comment Is university math all about proofs?
@John, I'll dispute that; sometimes they just have coffee instead.
May
4
comment How to integrate $\frac{1}{\sqrt{x^2+y^2+z^2}}$
Ah, right; the Jacobian is $r^2 \sin\phi$, so you cancelled everything correctly. The conclusion should now be clear.
May
4
comment How to integrate $\frac{1}{\sqrt{x^2+y^2+z^2}}$
@rekt, then your integrand times the Jacobian should only be $\sin\phi$, no?
May
4
comment How to integrate $\frac{1}{\sqrt{x^2+y^2+z^2}}$
rekt, did you remember to make the coordinate changes in your original integrand?
May
4
comment How to integrate $\frac{1}{\sqrt{x^2+y^2+z^2}}$
@Francesco, your spherical coordinate convention might just be different from the OP's.
May
3
comment Are all mathematicians human calculators?
@Mariano, Gauss did numerical analysis by hand, but of course he did not have computers, and we can't really say now if he's sane. :) On my part: I could do numerics by hand, but why should I bother?
May
3
comment A generalization of Bell numbers to arbitrary complex arguments
A related question. As I noted in the answer to the other question, one might consider using Cauchy's differentiation formula with an appropriate contour for numerical explorations. This is similar to the approach I made to generalize the partition numbers.
May
3
comment Invertible skew-symmetric matrix
To jump a bit forward: odd-order skew-symmetric matrices are necessarily singular, but even-order ones don't have to be.
May
3
comment Handling complex arguments of elliptic integrals in Maple
Most CAS suck at producing useful elliptic integral expressions. You might want to look at Byrd/Friedman and see if your particular form is in there.