5.8 Tuesday, November 8, 2016

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Top new questions this week: 
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[For a better animation of the solution from NDSolve] http://mathematica.stackexchange.com/questions/130502/for-a-better-animation-of-the-solution-from-ndsolve

I obtained a numerical solution from the following code with NDSolve

L = 20; 
tmax = 27; 
\[Sigma] = 2; 
myfun = First[h /. NDSolve[{D[h[x, y, t], t] + 
Div[h[x, y, t]^3*Grad[Laplacian[h[x, y, t], {x,  ...

- asked by jsxs (12 votes), answered by Nasser (14 votes)

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[A puzzling result of "FullSimplify"] http://mathematica.stackexchange.com/questions/130606/a-puzzling-result-of-fullsimplify

When I input:

FullSimplify[(1 - a^2)/b^2, a^2 + b^2 == 1]

the result is the ideal answer 1

Howeverif I input:

FullSimplify[(1 - b^2)/a^2, a^2 + b^2 == 1] 
 
 
the result is (1 - b^2)/a^2  ...

- asked by dabuyang (11 votes), answered by Bob Hanlon (7 votes)

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[ImageFeatureTrack or ImageDisplacements to measure average object velocities in images] http://mathematica.stackexchange.com/questions/130391/imagefeaturetrack-or-imagedisplacements-to-measure-average-object-velocities-in

I have as example a set of 30 gray scale images (8bit, 568*478 pixels, they are avalable here: http://tinyurl.com/zckyv9w where bright objects on dark background move from image to image mainly ...

- asked by mrz (9 votes), answered by Simon Woods (10 votes)

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[Documentation Tools: Don’t put web URL in user package docs] http://mathematica.stackexchange.com/questions/130515/documentation-tools-dont-put-web-url-in-user-package-docs

I am exploring the Workbench documentation tools for the first time and one of the difficulties I encountered was that every generated (compiled) documentation page includes weblinks. These point to ...

- asked by Szabolcs (9 votes)

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[How to make plots ’blacker’?] http://mathematica.stackexchange.com/questions/130471/how-to-make-plots-blacker

I need to make a contour plot for publication, but even if I 
set ContourStyle->Black, the 'black' plots and the axes are very faint. 
When I export the figure in svg and open it in some  ...

- asked by Physicist (9 votes), answered by Michael E2 (10 votes)

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[How to specify algebraic relations between objects?] http://mathematica.stackexchange.com/questions/130258/how-to-specify-algebraic-relations-between-objects

so I’m wanting to screw around a bit with Geometric Algebra in Mathematica. To start, I want to create some basis objects: \(e_1,~ e_2,~e_3\) and then specify the relations between them which are

- asked by Mason (9 votes), answered by march (9 votes)

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[Crack it If you Can? BUT in the BEST way] http://mathematica.stackexchange.com/questions/130566/crack-it-if-you-can-but-in-the-best-way

From the Wolfram Community:

Hello everyone,

A little while ago I was asked to solve this "safe cracker" puzzle, a sweet example of a coffee table puzzle. The basic gist of this puzzle is that it ...

- asked by Youphyso (8 votes), answered by george2079 (4 votes)

================================== Greatest hits from previous weeks: ==================================

[Writing a word with straight lines] http://mathematica.stackexchange.com/questions/113403/writing-a-word-with-straight-lines

Here is an interesting way to write a word: (it is from a poster for the International Museum Day 2006; I believe it even won an award at an international design competition)

by Boris Ljubicic. ...

- asked by VividD (72 votes), answered by Anton Antonov (34 votes)

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[Where can I find examples of good Mathematica programming practice?] http://mathematica.stackexchange.com/questions/18/where-can-i-find-examples-of-good-mathematica-programming-practice

I consider myself a pretty good Mathematica programmer, but I’m always looking out for ways to either improve my way of doing things in Mathematica, or to see if there’s something nifty that I haven’t ...

- asked by J. M. (441 votes), answered by faysou (396 votes)

================================== Can you answer these? ==================================

[Passing boolean parameters to a .NET Method using NETLink] http://mathematica.stackexchange.com/questions/130658/passing-boolean-parameters-to-a-net-method-using-netlink

According to the NETLink documentation, NETLink automatically handles type conversions from Mathematica to a .NET dll. One of the issues I have is that the .NET method I want to use expects a Boolean ...

- asked by user39464 (1 vote)

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[ParametricPlot3D Self Intersection] http://mathematica.stackexchange.com/questions/130460/parametricplot3d-self-intersection

I would like to know where my ParametricPlot3D intersects itself and to extract all intersections (points, lines, surfaces...) to animate them by changing P:

ParametricPlot3D[{fX[u,v,P], fY[u,v,P],  ...

- asked by chkone (3 votes)

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[Faster solution to combinatorial problem of two-part contractions] http://mathematica.stackexchange.com/questions/130598/faster-solution-to-combinatorial-problem-of-two-part-contractions

Given a list of elements I need all possible pairings of elements with a leading factor that describes the number of permutations. A (ugly but) working version would be:

list = {a, b, c, d}; 
 res =  ...

- asked by pbx (2 votes)