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bio website nl.linkedin.com/in/scdevries
location Utrecht, Netherlands
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visits member for 2 years, 3 months
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project euler


Apr
13
answered Trouble combining planet orbits and positions in Graphics3D and Show
Apr
13
comment Trouble combining planet orbits and positions in Graphics3D and Show
It looks like the scaling is in astronomical units, so a multiplication by 149597870700 should do the trick.
Apr
13
comment Trouble combining planet orbits and positions in Graphics3D and Show
If you study the output of AstronomicalData["Venus", "OrbitPath"] and compare it to the output of AstronomicalData["Venus", "Position"] you'll see that the former doesn't provide the actual path coordinates but some kind of scaled version with numbers differing orders of magnitude from the latter ones.
Apr
13
comment Imaginary number appears in Integrate
That doesn't work here, but ComplexExpand[\[CapitalTheta], TargetFunctions -> {Re, Im}] does.
Apr
13
comment Discrete Fourier Transform and data manipulate
Your calculation of dataX and dataY is a bit strange. When you change m[[#]][t] & /@ {1} in m[[1]][t] and the same for y, you can drop the two Transposes below and all your figures plot just fine.
Apr
13
comment Solving huge equations
Well, I managed to get a result by rewriting the equation to get rid of the square root. The results are in terms of Root objects and ConditionalExpressions and take many tens of pages. That won't do you any good.
Apr
13
comment Automatic replacing of [ with []
How about using FrontEndExecute[FrontEndToken["InsertMatchingBrackets"]] instead of the two FrontEndExecutes you used?
Apr
13
comment Z-Transforms and Floor Functions
From the definition of the z transform it seems to follow that x is an integer. So Floor[x] or x should be the same.
Apr
13
comment Automatic replacing of [ with []
Are aware of the fact that Alt-] inserts a matching [ ] pair? No modifications necessary.
Apr
13
reviewed Close RegionPlot of a Double integration
Apr
13
reviewed Reviewed iterative programming
Apr
12
reviewed Close Solution To Nonlinear System
Apr
12
comment Solution To Nonlinear System
You can download a trial version which should work for a month.
Apr
12
reviewed Close How can I modify my code so the result of my final calculation is acceptable to Simplify?
Apr
12
reviewed Leave Open I don't understand ListCorrelate!
Apr
12
reviewed Close how to solve this ode problem?
Apr
12
reviewed Reviewed How does GroupActionBase affect the order of elements in a group?
Apr
12
comment predator prey model with prey refuge
interesting, your default plot colors are not the v9 defaults... :)
Apr
12
comment Is it possible to get AltGr key to work in Math.exe?
Are you sure Mathematica is doing this and not Windows? And if you need Math.exe can't you just write a script in a text editor such as notepad?
Apr
12
comment predator prey model with prey refuge
An article about this system can be found here.