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2d
comment 3D orbits of moons around their respective planets
There's a fair bit of interest in Jupiter's 4 largest moons, so I'm somewhat surprised no one has done this (at least for Jupiter + the 4 big moons) yet. BTW, feel free to contact me (see my profile) if you want help in real time, and you can post the results here.
2d
comment 3D orbits of moons around their respective planets
I'm guessing you would use some combination of ParametricPlot3D and Animate? It would really depend on how you want the model to look.
2d
comment Fourier-style solutions to differential equations, not piecewise polynomials
@Nasser I did see a related question about taking the Fourier transform of the resulting InterpolationFunction(s), but that seems a bit roundabout and inaccurate. I want the original solutions themselves in Sin and Cos functions. Re differentiation, I meant that InterpolationOrder 3 means the resulting polynomials are of 3rd degree, so their 3rd derivatives must be discontinuous at boundary points.
Feb
6
asked Fourier-style solutions to differential equations, not piecewise polynomials
Feb
6
awarded  Enthusiast
Feb
5
comment Finding a seven-digit number with all of its prime factors less than 20?
This is a great answer since it even works for distinct primes. Of course, if the primes can repeat, 2^20 gets my vote.
Feb
4
comment Unstable command line startup time
What other processes are running? Try 'top' or 'uptime' (which gives current load average) before running Mathematica to see how busy the system is in general.
Feb
4
comment Popup window shows after kernel closed when using J/Link
This doesn't help you, but I get this message all the time when I interrupt Mathematica when running from the console. Clicking "yes" seems to work without causing any negative side effects.
Feb
4
comment 3D orbits of moons around their respective planets
You'll have to compute the ellipse yourself based on AstronomicalData["Ganymede", "OrbitRules"] or similar. Or you can use NASA's SPICE libraries and data if this is more than a casual query.
Feb
3
comment How to evaluate this integral with a bessel function
Is $\mu$ an arbitrary function here?
Feb
3
comment Tag Times is Protected
Did you fix all 4 missing semicolons in the (* calculations *) section? And, if so, could you post the revised code just to make sure we are looking at the same thing?
Jan
28
comment A function about prime gaps
I can't see an easy way of doing it. You'd have to build a table or do a While loop or something. I assume you're looking for an easier solution than that, yes?
Jan
28
comment FindRoot of interpolating function from NDSolve
Could you put the actual equations back into the main question instead of as a comment? I tried running them from the comment but got back "NDSolve::ndnum: Encountered non-numerical value for a derivative at t == 0..", so I'm guessing the cut and paste didn't work.
Jan
27
comment Wrong Limit[…] for inexact expressions
I meant setting a equal to 2*Pi-e and 2*Pi+e and then taking the limit. If Mathematica is accurate above, a small change in a makes the limit infinite.
Jan
27
answered Is there an easy way to do set counting in Mathematica?
Jan
27
comment Is there an easy way to do set counting in Mathematica?
I don't think Mathematica has this functionality builtin (the function Count[] does something else entirely), but it would be interesting to create something like this. Technically, your Count would be a functor since it acts on the category of sets. Currently, you can't set Length, so you'd need something like SetCardinality to do operations. Brief googling suggests no one has done this yet...
Jan
27
answered Wrong Limit[…] for inexact expressions
Jan
27
comment Wrong Limit[…] for inexact expressions
I think @Louis is saying that "2*Pi" and "2.*Pi" are different, but you already knew that. Try setting a to 2*Pi+e to see an odd result: apparently, there's a sign change in the limit near 2*Pi.
Jan
27
awarded  Autobiographer
Jan
25
comment How to scale a part of a curve horizontally and vertically?
Random thought: if you just need the stretched functions to look at, consider PlotRange?