21,531 reputation
12973
bio website
location
age
visits member for 2 years, 9 months
seen 29 mins ago

Oct
12
comment How to export a text into eps without splitting
it works fine for me. Version 10.01 on windows.
Oct
12
answered StateResponse is non-deterministic
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
11
answered Plot Complex Function
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
answered what to do when NSolve does not solve
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
answered Total by a criteria
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
revised Using mathematica to understand linear algebra
added color
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
revised Using mathematica to understand linear algebra
make the point sphere
Oct
8
revised Using mathematica to understand linear algebra
clean
Oct
8
answered Using mathematica to understand linear algebra
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"