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Oct
12
comment Why this gives 0?
Can you explain why the result should be sinh(x)? Lets assume all is perfect, and so InverseFourierTransform[FourierTransform[Cosh[t]]] should in theory return back Cosh[t], right? (inverse(fourier(foo))) is foo. Then why is I*Cosh[h]=Sinh[x]? Where did this come from?
Oct
12
comment How to export a text into eps without splitting
it works fine for me. Version 10.01 on windows.
Oct
11
comment How do I find the expression for where the first derivative equals 0?
Mathematica does not have Sqr function. !Mathematica graphics I am using V 10.01
Oct
10
comment Epilog with text not shown
You are telling it to put the text at {-12,10} but you are saying the plot range should be {-10,10} ? So it will not show up. Try Plot[x^2, {x, -13, 10}, Frame -> True, Epilog -> {Text[Style["S", FontFamily -> "Helvetica", Black, Bold, 20], {-12, 10}]}]
Oct
10
comment Convert matrix of strings to matrix of numbers
s = {"425060", "0.214235E+07", "0.48", "0.01", "0.39", "0.49", "0.01", "0.38", "1.64", "-1.65", "-2.13", "518"}; InternalStringToDouble[#] & /@ s`, see mathematica.stackexchange.com/questions/1737/…
Oct
10
comment Getting unwanted solution from Solve
Solution 3 is a result of solution 2 I do not understand what this means. Each one is an independent solution. You do not obtain one solution from another? Solution 4th is correct. Try: vars = {x[1], x[2], x[3], x[4], x[5], x[6], x[7]}; eqs = {x[7] == 0, 6 x[4] x[5] + 6 x[3] x[5] x[6] + z*x[4] x[7]^2 + z*x[4] x[5] x[7]^2 == 0}; sol = Solve[eqs, vars]; eqs /. sol[[4]] and this gives True. If you want solution over reals only, add the options Reals
Oct
9
comment Importing multiple files with a loop
what is the first file name? is it datafile.20.0000.out? so what is the last file full name? is it datafile.20.1010.out ? You can't have an index that is not discrete. So index 20.1 will not work.
Oct
9
comment Importing data from Matlab, using data in “NSolve” and send the results back to Matlab
try matlink matlink.org
Oct
8
comment Converting image data to array
use the ImageData[] command img=Import["ExampleData/lena.tif"]; data=ImageData[img];
Oct
8
comment Matrix Rational Canonical Form
@Ryker this was over a year ago. So I do not remember now. But feel free to try it, and you find a bug you can report it and will try to fix it. Make sure to include the input and the expected output to help me fix it. As far as I know the code is supposed to work ok.
Oct
8
comment Using mathematica to understand linear algebra
@ybeltukov thanks for the hint. I changed the point to sphere. yes, it looks better.
Oct
8
comment the default option of NDSolve
You can do Options[NDSolve] and see the default values. It says Automatic for some. Then go to each and looks at its help. For Accuracy it says AccuracyGoal->Automatic normally yields an accuracy goal equal to half the setting for WorkingPrecision and for PrecisionGoal it says ->Automatic normally yields a precision goal equal to half the setting for WorkingPrecision SO they depend on setting for WorkingPrecision Then you look at help for WorkingPrecision
Oct
8
comment Is there a command like meshgrid in Mathematica?
see mathematica.stackexchange.com/questions/30701/… "simulate-matlabs-meshgrid-function"
Oct
8
comment Matrix Rational Canonical Form
@Ryker I do not understand your question. The code is correct, unless you show otherwise. It produces the same result as on wiki, link above.
Oct
8
comment Using mathematica to understand linear algebra
First, you have error in the API, you wrote {{2 x - y, -x + 2y - z, 0 - 3 y + 4 z}, {x, -20, 20}} notice, you included a range specs inside the functions. i.e. you included {x, -20, 20} where it does not belong. Second, what is the parameters you are using? The helps shows that max of 2 parameters can be used, u and v. Are you sure ParametricPlot3D is what you want to use?
Oct
5
comment Attempt to solve for Differential Equation - Acc, Vel, Pos in (x,y,z)
it will be easier for someone to help you if you give the full code, which includes calling the function you have above. btw, in Mathematica functions are normally defined using := not =.
Oct
1
comment Outputting numbers symbolically
Table[HoldForm@2^n, {n, 1, 5}] !Mathematica graphics
Oct
1
comment Disable alert message with internet connectivity off
I have the same problem also. But it is a harmless beep that shows up only at start time, so it was easier to just ignore it than try to find how to turn it off :)
Oct
1
comment Using variable values from Manipulate in later Plots etc
Easy way around, is to use different symbol, since "t" is used as a free parameter inside Manipulate. From outside, refer to it as say "z", like this: Manipulate[ z = t /. First@NSolve[ Rationalize[Integrate[PDF[StudentTDistribution[0, 1, df], x], {x, -t, t}] == vertrauensintervall/100], t, Reals], {df, 3, 30, 1, Appearance -> "Labeled"}, {vertrauensintervall, 68.270, 99.73, 1, Appearance -> "Labeled"}, ContinuousAction -> False, LocalizeVariables -> False ] screen shot: !Mathematica graphics ps. need to @name to ping one so they hear you
Oct
1
comment ComplexExpand does not treat everything as real number
@belisarius I found a reference. Here it is reference.wolfram.com/language/guide/VariablesAndFunctions.html The symbolic language paradigm of the Wolfram Language takes the concept of variables and functions to a new level. I am sure there might be more exact definition somewhere, May be in the Wolfram Mathematica original book itself? I do not know.