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May
5
comment Problem solving a nonlinear partial differential diffusion equation
v10 manages to handle bc[[1]] and bc2[[1]]? I think they're redundant, actually they cause failures of NDSolve in v9.
May
5
comment Why does DSolve not give the expected analytical solution for a system of DAE?
Why you think your by-hand result is correct? Maple's result is the same as Mathematica's: i.stack.imgur.com/OYav3.png
May
4
comment Integral formula for the inverse Laplace transform doesn't work?
@Guesswhoitis. Long time no see, J.M. :) How about giving an answer? I'm not that familiar with Hankel contour.
May
4
comment Computing the coefficients for Gaussian integral
Is it a programming practice or you just need the Gaussian integral weights? If the latter, search GaussianQuadratureWeights in the document.
Apr
30
comment My simulation is not never finishing and it is taking so much time?
Well, "need to plot" isn't a reason for using numerical solution. The analytic solution can be used for plotting, too!
Apr
29
comment My simulation is not never finishing and it is taking so much time?
Is numerical solution necessary? Your equations can be solved analytically by DSolve.
Apr
29
comment Difficulty in getting correct Gaussian curve for diffusion of point source
Related: mathematica.stackexchange.com/a/71945/1871
Apr
29
comment Laplace transform of $\frac{1-\cos (t)}{t}$
I think you actually mean p == 2 t and the final line should be LaplaceTransform[2 Sin[t/2]^2/t, t, s], right?
Apr
28
comment Solving coupled differential equations with an eigenvalue
Seems that this hasn't been done: Hello, welcome to Mathematica.SE! I suggest the following: 1) As you receive help, try to give it too, by answering questions in your area of expertise. 2) Read the faq! 3) When you see good questions and answers, vote them up by clicking the gray triangles, because the credibility of the system is based on the reputation gained by users sharing their knowledge. Also, please remember to accept the answer, if any, that solves your problem, by clicking the checkmark sign!
Apr
28
comment Numerical solution of IVP for linear ODE with variable coefficient runs wild soon
You may want to take part in the discussion here :D, currently the transformation can be done by Assuming[0 < t < Pi/2, dChange[{y''[x] == (x^2 - 1) y[x], y[0] == 1, y[Infinity] == 0}, ArcTan@x == t, x, t, y[x]]].
Apr
27
comment Numerical solution of IVP for linear ODE with variable coefficient runs wild soon
The "DifferenceOrder" seems not to be helpful here, at least when it's together with "ImplicitRungeKutta" or "ExplicitRungeKutta"
Apr
27
comment Subsituting expressions for expressions
@F.E. I don't think there's any serious downside, it's just OK to use a[c] and b[d] directly. Of course it's better to use With when there's a lot of a[c]/b[d] to write.
Apr
25
comment In WolframAlpha, how can I make a Scatter Plot without connecting points?
Seems that parentheses aren't necessary: wolframalpha.com/input/…
Apr
23
comment Better method to swap the values of two 2-D arrays
There are two $a_{k+1,k+1}$ in the matrix?
Apr
23
comment Solving coupled differential equations with an eigenvalue
I noticed that you've modified your equations for several times, are you sure it's correct this time? Maybe you can show us the original problem?
Apr
23
comment Bizarre Compile Error, changing one symbol
Where's the definition of nSites?
Apr
21
comment Solving coupled differential equations with an eigenvalue
As mentioned above, ϕ[Ei] == 0 and ϕ'[Ei] == 0 give two equations, use either of them inside FindRoot or RootSearch will give you a result.
Apr
20
comment Analogue for Maple's dchange - change of variables in differential expressions
Your design for the syntax is undoubtedly more Mathematica-like and more reasonable. (I admit that when writing the question I haven't deliberated on the syntax design. )
Apr
18
comment Analogue for Maple's dchange - change of variables in differential expressions
@m0nhawk Well, as I mentioned above, that's just one of the related questions that are not general enough.
Apr
18
comment Integro differential eq boundary difficulties
I suggest you to add the $LaTeX$ or screenshot of your original PDE to your question. BTW, a simple mistake is exp should be Exp.