Mathematica

find index in an array
I work in an environment where another system is the dominant analysis tool. In porting some code to my preferred work environment, Mathematica, I find that I occasionally need to reinvent functionality found in the other system. One such function is find(). In that system, this function returns all the non-zero in... 9 Mar 2010 07:49

Simple question
Dear all Why doesn't the following statement give me "True"? Aren't both sides equal? a \!\( \*SubsuperscriptBox[\(\[Integral]\), \(0\), \(r\)]\(f[ r] \[DifferentialD]r\)\) == \!\( \*SubsuperscriptBox[\(\[Integral]\), \(0\), \(r\)]\(\(a\ f[ r]\) \[DifferentialD]r\)\) Thanks in anticipation f... 13 Mar 2010 08:37

Putting a Plot inside a Graphics function with
hello, fortunatly in Mathematica you can combine very easily. Just look at the heads - the all have to be of type Graphcis OR Graphics3D and then use Show[gr1,gr2,gr3,...] (in your case Show[Plot[...],Graphics[Disk...]] would work) PS: If you want to have more control on what to combine use the options Epilo... 8 Mar 2010 06:23

ReplaceRepeated in case of non ordered expressions
Hi; I have such equations: x=a+b y=c+d a=z+t b=y I want to use mathematica in order to simplify x and obtain: x=z+t+c +d I have used: [x,Listofequations] This function is available if I have equations written in the following order: x=a+b a=z+t b=y y=c+d but in the case of non ordered equations, it... 9 Mar 2010 07:49

Getting nice PlotMarkers, and some more ListPlot styling
I'm making a ListPlot and I'm trying to use the PlotMarkers option. I see that there are a few nice examples of markers in the docs: http://reference.wolfram.com/mathematica/ref/PlotMarkers.html But there is no mention of where I can see all the markers and choose from. I'd want an elongated marker, something l... 9 Mar 2010 06:43

Forcing mathematica to output a certain form
As a result of an Eliminate function, and subsequent (wrapper) simplification under some conditions, I am getting a non-linear differential equation. It looks like: f(t)+g(t) y'(t)=h(t) y^2(t) Is there a way to force mathematica to output this in the way a differential equation is best written: y'(t)+h(t... 12 Mar 2010 08:18

Putting a Plot inside a Graphics function with other drawings
Hello, (Please ignore my earlier question about plot markers, I already figured it out, thanks.) I am trying to combine a Plot with other graphics elements. I've tried doing Graphics[{Plot[whatever], Disk[whatever]}], but it's saying that "Graphics is not a Graphics directive." (Probably because Plot already ... 9 Mar 2010 06:43

Remote Kernel
Hello everybody, I would like to connect to a remote kernel in Mathematica, and according to the Mathematica documentation this should be fairly easy. In "Evaluation -> Kernel Configuration Options", I have added a new kernel with the following options: Remote machine Kernel program: /Applications/Mathemati... 7 Mar 2010 05:15

Conjugate of symbolic expressions
I have been using Mathematica 7 to do the grunt work in solving some transmission-line problems, using the exponential form of the equations. A typical form would be S1 = Exp[k1*x + I*omega*(t+tau)], describing signal one, where K1 is the attenuation in nepers per meter, I is the square root of minus one, om... 10 Mar 2010 01:57

Solving ODE with discontinuous shock perturbation [was: Modification
Here's my final solution and a new question. This solves a basic oscillator coupled to a growth equation, with the addition of a discontinuity, that when F reaches 5 from below, it drops to half it's value. Using NestList NDSolve is restarted at each discontinuity, and a method of piecewise evaluating the solution ... 7 Mar 2010 05:15