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Mar
26
comment Solving a system of 4 logarithmic equations?
I'm just curious why you posted an answer that finds a non-solution eight hours after RiemannZeta already proved that there are no solutions.
Mar
26
comment Solving a system of 4 logarithmic equations?
I get a warning, FindRoot::cvmit: Failed to converge to the requested accuracy or precision within 100 iterations. And substituting the values into the equations gives $11.5863 = 20$, $6.32768 = 125$, $4.74367 = 710$, $4.49181 = 1350$.
Mar
24
comment Area of a convex polygon with a set of points
If your polygon is known to be convex then ordering by angle relative to the mean of the vertices will also work.
Mar
22
comment Eigenvector Anomaly
@rm-rf: Done. I hope Peter doesn't mind.
Mar
22
revised Eigenvector Anomaly
changed to a question about Mathematica
Mar
22
comment Eigenvector Anomaly
If we edited the question to replace the W|A queries with Mathematica commands, the difference would remain and the question would be on-topic. But is that too radical a change from the original question?
Mar
21
comment Choosing $n$ equidistant points on a circle with given radius and center
@Pavithran Your code creates $n+1$ points of which the first and last are the same. I'm not sure that's what you want.
Mar
19
comment Plot 3D density
Have you tried ListContourPlot3D? By the way, your title is misleading: this is a 3D density, that is, a density over a three-dimensional region.
Mar
18
comment How can I define a 3d-body through different views?
Here's a smooth plot of what I think is the same object: ContourPlot3D[x^2 + (y/(1 - z))^2 == 1, {x, -1, 1}, {y, -1, 1}, {z, 0, 1}, BoxRatios -> Automatic] i.stack.imgur.com/CIqpO.png
Mar
17
comment Find the eigenvector associated with the smallest eigenvalue, not smallest in magnitude
I would have suggested finding the eigenvectors of $I + \epsilon A$ for sufficiently small $\epsilon$, but since you don't have a lower bound for the smallest eigenvalue you can't be sure that $\epsilon$ is sufficiently small. And in any case this might amplify the numerical error you incur.
Mar
12
comment What type of solver does Mathematica use in LinearSolve
How on earth can any solver fail on a diagonal matrix?
Mar
8
comment How do I NOT change the input/output number when editing?
Yes, this does sound like a case of "Doctor, doctor, it hurts when I do this." "So don't do that then."
Mar
7
comment 2D Fourier transform of a table - ArrayPlot issue
I guess what you're looking for is an analogue of Matlab's fftshift. It's not really an issue with ArrayPlot, it's an question of visualizing the result of the Fourier transform.
Mar
5
comment Colorize a 3D distribution of points according to density
Unfortunately SmoothKernelDistribution is new in 8.0.
Mar
4
comment How to obtain differential equations of motion using Lagrangian dynamics?
@Nasser: "You do not really count the unstretched length of the spring is L in these problems, since one always starts from the relaxed position. The initial stretched length of the spring is already account for." This is quite incorrect. Only if the problem is one-dimensional, and one end of the spring is fixed, and you choose the origin of the coordinate system at the relaxed position of the other end, then your statement is valid. This is not the case for this problem.
Mar
4
comment Variance/Standard Deviation with a Constant Vaule
For one thing, Variance expects a list, so you'd need to do Variance[{10}] instead. But for another thing, Variance returns the sample variance, with $n-1$ in the denominator, so the variance of a sample of length $n=1$ is not defined at all.
Mar
3
comment Manipulating infinite series
Don't you want -Sum[f[x], {x, m, m+2}] instead?
Mar
1
revised StreamPlot for Bifurcation Diagram
added 521 characters in body
Mar
1
answered StreamPlot for Bifurcation Diagram
Feb
28
comment Finding the optimal teams ranking based on the table of match results
Are you absolutely sure you want to iterate over all 90 billion permutations? That's a lot of iterations. If I were you, I'd first ask on math.stackexchange.com whether there exists a more efficient algorithm that doesn't take superexponential time, and then implement that instead.