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10h
comment An unexpected NDSolve behavior
I have to apologize, the whole question is the result of my stupid mistake Plot[Evaluate[y /. nds], {y, 0, 30}] instead of Plot[Evaluate[y /. nds], {t, 0, 30}] . I propose to close this question as the one based on a simple mistake.
12h
comment An unexpected NDSolve behavior
@Quantum_Oli No, in that case Mma returns the empty plot. And besides, the question is different. Whatever the way I obtained it, the plot should show a cosine, rather than a straight line.
12h
asked An unexpected NDSolve behavior
1d
comment What is it with MemberQ?
@happy fish Yes, but otherwise it refused to accept my question.
1d
answered Can highlight an expression in mathematica in an expansion?
1d
asked What is it with MemberQ?
2d
comment How to change the default stylesheet?
There were some time ago "Notes on Creating Style Sheets" by David Park. He published them on MathGroup at that time. It is a very nice and comprehensive explanation which I use ever since. However, I do not think it is possible to publish here a document of somebody else. You might, however, want to ask him directly. In such a case go to his homepage, davidandalicepark.wordpress.com/home-2/about-3 where you will find his e-mail.
2d
answered Metric Simplify & grouping
2d
comment Strange DiracDelta integration results in 10.4.1
I confirm the result for 10.4.1
Apr
26
comment JournalArticle does not react on the PointSize option
@Rashid Thank you, Rashid. This is a workaround. However, itself the presence of the PlotMarkers without being asked is a nonsense, if not a bug. One needs to look for a workaround. Say, like this: ListPlot[Table[Table[{i, j*i}, {i, 1, 10}], {j, 1, 3}], PlotMarkers -> None, PlotStyle -> {PointSize[0.01], PointSize[0.05], PointSize[0.1]}] .
Apr
25
asked JournalArticle does not react on the PointSize option
Apr
25
comment Where is the file Default.nb?
During the StyleSheet modification you cannot save the modified file by Menu/File/Save. You need to use Menu/File/SaveAs even if you have already saved it once. However, I join to m_goldenberg warning: never, never change Default.nb. Make better something like Default-modified.nb, as I did for myself. You will need to assign each new notebook to this style, but you will be on the safe side.
Apr
23
answered how to find sum of variable c1+c2+c3 for expression combinations
Apr
23
comment Plotting cicle using ListPlot
@Gelios MatrixForm is for visualization only, not for further calculation or plotting.
Apr
22
comment Using assumptions with Integrate
It works for me, though takes about a minute to calculate (Win7 Mma10.4.1)
Apr
22
answered Plotting cicle using ListPlot
Apr
22
comment What is the meaning of “/.”?
Evaluate this: ?/. in Mma and you will see the hint.
Apr
22
comment Colour bar for contour 2D graph
Please publish (at least a small part of) your arrayData. Otherwise we cannot try and see, how we can help you.
Apr
22
comment Numerical derivative from data points
Continuation: You should understand that taking the same data and few times adding random numbers to it (depending upon the noise amplitude) you may obtain for the derivatives results very much different from one another. Just because numerically the first derivative is (y2-y1)/(x2-x1) and you add to y2 and y1 some different random numbers. The derivative takes the form: (y2+dy2-y1-dy1)/(x2-x1). Then everything depends upon the ratios dy2/y2 and dy1/y1. It is still worse with the second derivative.
Apr
22
comment Numerical derivative from data points
To address your edits: I think that the problem is unclear formulated. It can have several answers. To prefer one of them one needs to know some more information that you probably keep in head, but do not write. (1) Where did the data come from? (2) Why do you add a noise to it? (3) What is expected from the function in question?