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2d
comment Problems with QueueingNetworkProcess
Your code is not valid actually. You are calling the function using shoppingProcess[s_]. This should be the definition of the function, not in the call. In the call, do not use _ on the argument.
2d
comment Fourier-style solutions to differential equations, not piecewise polynomials
I do not understand the problem. Can you show an example where you could not differentiate InterpolatingFunction returned from NDSolve? But you could always find the Fourier series approximation of the InterpolatingFunction returned If this is what you want. It will not be any better than piecewise polynomials, due to Gibbs phenomenon to start with.
Jan
31
comment Non Standard Eigenfunction Plots of the Laplacian Over the Unit Square
fyi; Here is a demo that also plots the modes demonstrations.wolfram.com/VibrationOfARectangularMembrane
Jan
31
comment Symbolic derivatives and substitution
What you say should be the result is actually wrong. Try D[x h[x, y], {x, 2}] to see. btw, it might be easier just to make a function. r[expr_] := D[expr, {x, 2}]; then you can do r[f[x, y]] and r[x h[x, y]]
Jan
31
comment How to plot points in 2D without restricting their apparent positions to pixel grid?
You also defining a function use =. This should really be =:.
Jan
31
comment How to plot points in 2D without restricting their apparent positions to pixel grid?
There is no difference. Both "vibrate" the same way. Try this to see it better Manipulate[ Row[{ Graphics[ {PointSize[Large], Point[{0, x[t]}]}, PlotRange -> {{-0.1, 0.1}, {-0.1, 1.1}}, Axes -> False, ImageSize -> 50], Graphics3D[{PointSize[Large], Point[{0, x[t], 0}]}, PlotRange -> {{-0.1, 0.1}, {-0.1, 1.1}, All}, Boxed -> False, ImageSize -> 50, ViewVector -> {0, 0, 10^4}] }], {{t, .1, "time"}, .1, 100, .1, Appearance -> "Labeled", ContinuousAction -> True}, ControlPlacement -> Left, Initialization :> ( x[t_] := Abs@Sin[t]/t ) ]
Jan
17
comment What are some “real-world” applications of Mathematica?
Related question has answers here mathematica-application-in-real-life
Jan
17
comment What are some “real-world” applications of Mathematica?
Wolfram alpha is a real world application written in Mathematica: The secret weapon that has allowed us, and no one else, to assemble such a vast library of algorithms, in such a diverse range of fields, is Mathematica. from the-secret-behind-the-computational-engine-in-wolframalpha also half of Mathematica itself is written using Mathematica. I think about 50% is C/C++ and the other half is in Mathematica. This might have changed in recent versions. I remember reading this sometime ago.
Jan
11
comment Order of evaluation - does Mathematica evaluate variables before or after substitution?
Each symbol can have a value associated with it or not. When you write y=x^2, then later on, write x=10, then y now automatically becomes 100 since it was pointing to x before, but now x has a value which is 10. There is no explicit evaluation of y. It is done automatically. It is all linked lists. If a symbol x has value other than itself, then its value is used automatically when looking up y.
Jan
11
comment How to fill in missing points on a graph?
If you add PlotTheme -> "Classic" then you will not notice this.
Jan
11
comment What's is the restrictions for the function MatrixExp?
from help works only on square matrices. So as long as the matrix is square, it will work.
Jan
11
comment Plotting x^(1/3)
(-8)^(1/3)=-2, How did you get this? it is complex number?
Jan
9
comment new kernel crashes using DSolve in 10.3.1
Thanks for trying. It crashes all the time on my Mathematica. May be there is something different in my system. Using service pack 1, windows 7. On fresh kernel. I can reproduce this all the time. I wish there is a dump file or some other log that the kernel writes when it crashes. This is very annoying that there is no log or dump file generated to look at.
Jan
9
comment new kernel crashes using DSolve in 10.3.1
@b.gatessucks thanks for checking. It must be a windows only issue then. I am using windows 7, service pack 1, 64 bit.
Jan
9
comment series to rational order
same with Maple: series(x^(1/4)+x^(1/3)+x^(1/2), x=0,1/3 ); gives Error, invalid input: series expects its 3rd argument, n, to be of type {infinity, nonnegint}, but received 1/3
Jan
9
comment Why doesn't replace and evaluate?
see replace-rule-with-function-derivatives-dont-evaluate and replace-function-and-its-derivatives-found-with-solve
Jan
9
comment How can I obtain the same result without using any loop?
You might want to do f[n_] := f[n] = n + f[n - 1]^2;
Jan
8
comment Plot Command With Clean Grid Lines
@AxelF exactly. After making that "fix" in the question there, my Mathematica got inflicted with the dreaded Formatting Notebook Contents problem each time I open any new notebook or do anything. So I removed the graphic card update and went back to the yellow Mathematica, but now without having to suffer with Formatting Notebook Contents. 10.3.1 on windows 7, 64 bit.
Jan
7
comment how to import plain text file, with mixed formats with strings that contain commas
@m_goldberg OMG! You are right. I used the wrong 3 letters. When I changed the file name to test.csv from test.cvs then it worked :) Sorry about the confusion. You method also works. I have a pharmacy called CVS next to where I live, may be that is why I made this mistake.
Jan
7
comment how to import plain text file, with mixed formats with strings that contain commas
@m_goldberg if I just use Import["test.csv"] I do not get an error, but the data read is one long string. Which is not what I want. If I use Import["test.csv","CVS"] I get an error. I do not know why you did not get one long string on your end. Here is screen shot: !Mathematica graphics