Mathematica Definition and 1000 Threads

kron[m_,n_]:=\!\( \*SubsuperscriptBox[\(\[Integral]\), \(0\), \(2\)]\(\(Sin[ \*FractionBox[\(n\ \[Pi]\ x\), \(2\)]]\ Sin[ \*FractionBox[\(m\ \[Pi]\ x\), \(2\)]]\) \[DifferentialD]x\)\) This is the integral over x of sin(n pi x / 2) times sin(m pi x / 2) from 0 to 2. This is one way to...

I posted this first in the homework section, but no one answered it. I figured this might be a better section... I have multiple 1D data sets, let's call them data1, data2, data3, etc. Each data set has the same number of entries. Each one is either a row or a column (I can just use...

Homework Statement I have multiple 1D data sets, let's call them data1, data2, data3, etc. Each data set has the same number of entries. Each one is either a row or a column (I can just use Transpose[...], so same] and when I use the ListPlot[] function, I get a graph where the vertical axis...

Hi all, I've been getting Mathematica to do some integrals for me, which are typically returning sums of Meijer-G functions. When I try and obtain numerical values for these sums, some of my results have contained terms which Mathematica has refused to evaluate numerically; an example is...

ok, I have tried and failed. How does one graph the following on mathematica in 3D: \left( x^{2} + \frac{9}{4} x^{2} + z^{2} -1\right)^{3} - x^{2}z^{3} - \frac{9}{80}y^{2}z^{3} =0 with -3 \leq x,y,z\leq3 If someone could give me the command (what to enter), that would help. Heres what I...

Hi Guys, I am new to mathematica. I have gotten it to do an integration for me, then simplified the answer using FullSimplify. It does a very good job, but I can see that a futher symbolic substitution would make it even nicer, e.g. I would like to define A = b*x*t. So where ever there is...

I was about to do an experiment in Wolfram Mathematica like drawing electric field lines around a charged body and other arrangements. So i saw this nifty little Function for that very purpose called VectorPlot My Problem is that i don't know what the function does exactly i went through...

Hello, I would like to know, how can I change units showed in axis. I would like to change those relative units (20000, 40000...) to μm. The conversional relation is 50 = 1μm, so instead 20000, 40000 i would like to have 400μm, 800μm. I enclose picture where it should be more clear what I am...

hey, I have this group I've been trying to generate using the GenerateGroupoidByRelations[] function but it keeps giving me an error, G = GenerateGroupoidByRelations[{a, b}, {a^4 == e, b^4 == e, a ** b ** a ** b == e, a^3 ** b ** a^3 ** b == e}, SizeLimit -> 60] gives...

Hi, I need to generate some data in a Table and then be able to do all kinds of matrix and other mathematical operations on them. Right now I am testing the commands but am unable to get them to work. My table has this extra parenthesis floating around which I'm not sure how to get rid of...

I'm having trouble solving this summation and was wondering if anyone could put me on the right track. Here's the problem below, I've also attached a pdf of it. Sum from 1 to infinity in steps of 2 for l, m, and n:((-1)^((m - 1)/2))*(m/(n^2 + l^2 + m^2)) I've tried using the built in sum...

how can I get data from a certain equation using Mathematica in order to plot them using MATLAB command (imagesc) !

Could someone tell me how I would go about plotting a function in Mathematica over say, x^2? or sqrt(x)? Thanks!

Can anyone help on this? I am calculating the magnetic susceptibility, essentially a second derivative evaluated at zero magnetic field. The problem is that sometimes Mathematica works perfectly, and sometimes it gives me a "1/0 complexinfinity" error message, with no obvious reason. The...

Hello everyone. This is my first post after looking for information about a simple question. Unfortunately I didn't found information in any other posts in this forum so, here we go! I'm trying to solve numerically a set of N ODEs with Mathematica 7.0. Let me call x(t) an array of N...

Hello, everyone. I have a rather bizzarre problem. I wrote a code that takes a matrix U[1] and calculates a matrix U[2] from it using simple math. I wrote three For loops, one to go across the U[n], the other two to read the matrix U[n] across all the lines and columns. I do it twice because...

First post on this forum, that IMO is amazing! I was reading the introduction of the book “A gentle introduction to the art of Mathematics” and I was wondering about what the authors wrote on whom the book is for. In particular he stated that the book is in particular for people who can...

I have a Plot using Frame, and AxesOrigin set to a convenient value. The plot process offsets the physical origin of the Frame so that the specified AxesOrigin is just inside the Frame border - ie there is an offset introduced for both axes. Is there a way to tell Mathematica not to set any...

I am trying to plot the following function: \sigma(r, \phi) = \frac{3r^2}{\sqrt{1 - r^2}} e^{i(2 \phi - \omega t)} where \sigma is a surface density, r is radius, and \phi is azimuthal angle. It is supposed to yield a "bar shape" for a galactic disk, but I'm not sure how to go about...

I have a function of two variables, f(a,b). I want to create a series of 2D plots (on the same plot) of f(a,b) vs a, for a=1 to 10, for a set of discrete values of b (e.g. b=10,20,50,100). Is there a simple way to do this? Plot3D works, but I cannot find how to do it in 2D. DN

Hello, having usually used MatLab, I am just beginning to use Mathematica. I am having trouble locating packages, however. In particular, I'd like to download: http://reference.wolfram.com/mathematica/VectorAnalysis/tutorial/VectorAnalysis.html (Vector Analysis)...

Homework Statement Find the parametric equations in the surface S therefore Z^2=1+x^2+y^2 and 2 ≤z ≤3 and draw the image of the surface with Mathematica Homework Equations (below 3.) The Attempt at a Solution Use polar coordinates as parameters. The surface defined is part of...

Hi I have the following graphic: Graphics[{Opacity[0.5], Rectangle[{0, 0}, {1, 3}]}] Say I want opacity to vary with x, e.g. with the expression opacity = x^2. Is there a way to do this? I checked out the "Help", but there were no examples of a varying opacity. Niles.

Hi everybody, sorry for the inconvenience. I try to plot the poincarè map of the restricted three body problem. I find in this forum the follow script that do this for the Lorenz system: mysol = NDSolve[{x'[t] == -3 (x[t] - y[t]), y'[t] == -x[t] z[t] + 26.5 x[t] - y[t], z'[t] ==...

Hi! I am wondering if someone could help me write a function in Mathematica. What I would like it to do is take another function g as its argument and return the sum of g derived to all of its arguments (and multiplied by a scalar Δxi) f\left[g\left[x_1,x_2,\text{...},x_n\right]\right] =...

I have problems in computer intensive calculations, obtaining a message saying "Your Mac OS X startup disk has no more space available for application memory" Obviously, Mathematica's temporary working-file folder fills up the disk and has no more space. I asked Wolfram Research's...

I would like to be able to write my integrand before my integral and then have my integral be more compact. However Mathematica does not seem to like when I try and substitute in my dq's. Is there a way to tell mathematica to evaluate the substitution before evaluating the integral?(and, I...

Hi I have a long procedure, which calculates the potential of a physical system. The procedure returns something having the form potential = 1/(constant + z) where z is a variable. Now, I need to evaluate potential at different z. I can of course do something like z = 1; potential...

I was talking to my professor and I am tying to generate a phase curve that looks like (see attached).However, I am only been able to generate phase portraits.I need to generate a plot that does that.From these equations,$$\dot{x} = -x + ay +x^2y$$$$\dot{y} = b -ay-x^2y$$Here is what I have been...

Hi I am succesfully using NDSolve to find the solution of a 1D equation of motion: solution = NDSolve[{x''[t] == -200, x[0] == 0, x'[0] == 100}, x, {t, 0, 1}]; ParametricPlot[{x[t], x'[t]} /. solution, {t, 0, 1}, PlotRange -> {{0, 100}, {0, 100}}] This is a particle decelerating constantly in...

Greetings PF. I am new to the subject of numerical methods and I'm interested in using the Adams method in Mathematica, this one with a predictor-corrector algorithm, to numerically solve a system of differential equations (first-order system). As I'm pretty green I was reading this page...

Hello, I was looking at ways I could optimize a simulation I wrote in Mathematica and came across the command compile. From what I understand, it defines a function that expects a numerical value for the variable. But I don't understand how this would be any different from just ordinarily...

How can I plot this in Mathematica?

I am trying to use NDSolve to solve a Schrodinger equation. My question is that if I want to solve the Schrodinger equation for an infinite wall potential at r = R, I would want my wave function to die at r = R. Here is the code that I know for a square well potential; NDSolve[...

Hi all, I've been using Mathematica through my school for a couple of years, and I finally got my own license so I can work on my homework when I'm not connected to the campus network (we can run Mathematica on our laptops as long as we can remotely hook up to the server they host it on)...

I am having trouble with ListPlot in combination with Manipulate. I can't see why it doesn't do what I tell it to. What I'm trying to do: I have several functions that is dependent upon one parameter t. These functions I got from solving a system with DSolve. I'd like to see their values...

I am running some notebook, developed by someone else, in mathematica. One of the function defined in the notebook will show a graph. Since the notebook is kinda messy and I don't want to modify it. To alter the title and/or style of the graph, I try the following G = ShowMapping[2.3]...

Hi, I don't understand how to remove the values for these subscripted variables once I have assigned a number to them. If I try to remove the value from a_1 below, I get an error message: Remove[a] Subscript[a, 1] = 1; myf = z^3 + z*w^2 myf /. z -> Subscript[a, 1] myf /. z ->...

Why is this happening (see picture)?

Hi I have a data set of the form: data = {{0, 0}, {1, 1}, {2, 2}, {3, 20}, {4, 1}, {20, 1}, {21, 1}, {22, 0}}; This data set is a probability density function (PDF), and I need to be able to integrate it from 0 to some x<22. I thought that I would use an interpolating function for...

Hi, I'd like to solve a DE, create a function with the solution, then use that solution in a Piecewise function, and then NIntegrate the Piecewise function but I can't get NIntegate to work. Here's what I'm trying to do: mysol = NDSolve[{y'[x] == x, y[0] == 1}, y, {x, 0, 1}] myy[x_] :=...

I'm having issues solving a 1st order ODE. Here what happens: NDSolve[{y'[x]/y[x] == k *Pi* r^2* Sqrt[1 + y'[x]^2], y[0] == 136/10}, y[x], {x, 0, 30}] NDSolve::ndnum: Encountered non-numerical value for a derivative at x == 0. Changing the x range is no help... I get the same message for...

Homework Statement This is for a lab, which I'm working on at home. There are two parts: using Mathematica to simulate a magnetic pendulum with 3 magnets by plotting the path of the bob and then extend my code to determine where the bob endpoint for all starting positions and draw the fractal...

Hey! So when I enter this in Mathematica In[246] = ZTransform[Sum[f[k] g[k - n], {k, 0, n}], n, z] InverseZTransform[%, z, n] I get: Out[246] = ZTransform[f[n], n, z] ZTransform[g[-n], n, z] Out[247] = InverseZTransform[ZTransform[f[n], n, z] ZTransform[g[-n], n, z], z, n]...

I'm ploting a simple function (the effective gravitationnal potentiel with angular momentum part) with Mathematica, and I'm getting some truncated curves close to the vertical asymptote located at r = 0 (see the picture below). Of course, this is normal since the function V(r) diverges at r =...

I need to define two functions for a molecule with speed s. a)it has a horizontal velocity between -s and s b) v , the vertical velocity between +Sqrt[s^2-u^2] and -Sqrt[s^2-u^2] This is what I have done for a) f[s_]:=RandomReal[{-s,s}] for b)...

Hello every one, I need help please... How to write in mathematica to solve an equation of x and y that is equal to 0, (i.e. y^4+2y^2x^2-15x=0) and let the program try all the value of x=0,1,2,3,...,10000. and all the value of y=0,1,2,3,...,100. The program should start with x=0 and try all...

Does anyone know how would I go about making a point , bounce up and down in a box in mathematica? Would greatly apperciate for any help.. Thanks

Hi I am trying to do some problem from the book "Student's Introduction to Mathematica" 2ed. I have shown the snapshot of the problem in 1.png. My attempt is a snapshot in 2.png. Please suggest some ways to do this correctly. thanks

Hi guys, I seem to still be having problems formatting polynomials in a standard way in Mathematica. I generate them randomly and would like them output using Print in a particular format. Say I have: theFunction=-2 + w^3 (-9 - 3 z) - 7 z + w^2 (4 + 5 z) + w (8 - 2 z^2) + w^4 (-5 z^2...