Mathematica Definition and 1000 Threads

  1. E

    Recognize a product of two vars in Mathematica?

    I am wondering if anyone can tell me how to get Mathematica to recognize the product of two variables so that I can do things like take limits. For example, if I had a function F[x] = x*(R*W)^2 + 4*x and I want Mathematica to take the limit as (R*W)->0, how can this be done? I realize this...
  2. W

    Mathematica Mathematica Animation for power point?

    Is there a way to animate and export a 3D plot such that it rotates about the z axis automatically? A friend is doing a presentation and I'd like to make some animated files of the 3D plots we've been making to include in a power-point. I've looked through help files and some google searches...
  3. K

    Mathematica Mathematica for Poincaré sections - or maybe a different tool?

    Hi, I have a system of ODE's for which I want to compute points for a Poincaré section. I used NDSolve and EventHandler in Mathematica but EventHandler appears rather messy/limited for my condition: Suppose I want to save 4 iterations of a Poincaré map and then abort integration imediately...
  4. W

    Mathematica Mathematica 3D plotting question

    I'd like to make a single 3D graph that contains a scatter plot and a plane. Ideally I'd like to import the data for the point from an excel file, but if I have to punch it in, I can find a few hours to kill. Anyway, can anyone help me with the code for this? I can get a 3D scatter plot where...
  5. Rasalhague

    Mathematica Integrating Mathematical Functions in Mathematica

    I'm new to Mathematica. I used it to integrate the scalar field f:\mathbb{R}^3 \to \mathbb{R} \; \bigg| \;f(x,y,x)=z^2 over the top half of a unit sphere centered on the origin, paramaterising this surface with \phi: \mathbb{R}^2 \rightarrow \mathbb{R}^3 \; \bigg| \; \phi(r,\theta)=(r...
  6. P

    Mathematica Problem with simplification in Mathematica

    Assuming[a>0 && b>0 && c>0, FullSimplify[a+Sqrt[b+c]-Sqrt[a^2+b+c+2 a Sqrt[b+c]]]] does not simplify it to zero. Although output of FullSimplify[a+Sqrt[b+c]-Sqrt[a^2+b+c+2 a Sqrt[b+c]]==0] is true, even without any assumptions. Can anyone please resolve this puzzle...Thanks
  7. M

    Mathematica Mastering Mathematica Plotting: Tips and Tricks for Visualizing Your Data

    I have some data I imported into Mathematica. It has three columns. I want to plot col1 vs. col2, col2 vs. col3, and col1 vs. col3. I started out doing this Flatten[Partition[data, 3]] to get one long list. I'm kind of lost. Any help is appreciated!
  8. G

    Mathematica [Mathematica] Saving definitions

    Hi, I'm trying to save (into a file) definitions of some variables which are of the form Subscript[A,1], Subscript[A,2],... where the subscript is used as an index for the variable. When using the Save command I obtain the error Save::sym: Argument A1 at position 2 is expected to be a...
  9. N

    Mathematica Mathematica: minimize black box function

    I have a user-defined function that doesn't seem to work with NMinimum, FindMinimum, or any of the other optimization commands. I think this is due to the fact that the function uses elliptic integrals and matricies to obtain an output. It has multiple variables, but I want to keep them all...
  10. S

    Mathematica: Eigenvalues for a large symbolic matrix

    I'm trying to compute the eigenvalues for a 32x32 symbolic matrix (with one variable) in Mathematica. I get the following error: Eigenvalues::eival: Unable to find all roots of the characteristic \ polynomial. >> What could be a possible way to proceed? Thanks, Schez
  11. H

    Mathematica style touch screen program

    Hey I'm wondering if anyone has ever heard or knows of a touch screen program that would maybe use something similar to the Mathematica engine. I have seen some handheld touch screen computers for very cheap. It would be really useful(and just plain awesome) to be able to create equations and...
  12. A

    Mathematica: How do I program this? Square free part of an integer

    I am attempting to program Mathematica to multiply the square free terms of an integer. Basically say we are looking at 252, its prime factors are 2^2*3^2*7. So what I want to do is have Mathematica return to me just 2*3*7 when I enter 252. So I have this S := FactorInteger[252]...
  13. H

    Mathematica Mathematica taking a long time to solve

    Hi everyone, I am trying to solve this complicated two simultaneous equations, and it has been taking more than 2 hours to solve .. and it is still running... can anyone tell me what is wrong .. thanks Solve[{((((1 - xr)/xr)^(1/2) (M2^2 xr - 1)/( 1 + (gam + 1)/2 M2^2 - M2^2 xr)) -...
  14. K

    MATLAB Mathematica widely underrated in Physics? Matlab widely overrated?

    Hi, I have always been in love with computers and started programing early. When I started my studies in Physics like three years ago, people often recommended Matlab. I spent a lot of my spare time playing with it (e.g. solving ODEs, plotting solution, animating, plotting and evaluating...
  15. B

    How to Equate Two Solutions in Mathematica for Variable J?

    hi, I have two equations that I have used the Solve function in Mathematica to solve for A in both equations What I am having trouble with is trying to equate the results and solving for another variable J automatically Basically this is what I want to do: Solve[Eqn1, A] It gives {{A ->...
  16. H

    Mathematica Help: Plotting y=k-x/k for All -10<k<10

    Hi, Guys Can someone help me about this question? I am trying to use Mathematica to plot all the functions: y=k-x/k for all -10<k<10 with interval of 0.1 what I wrote is like this: Plot[Table[k-x/k,{k,-10,10,0.1}],{x,-10,10}] However, because the function doesn't have meaning when k=0...
  17. S

    Mathematica Changing interval in Histogram, Mathematica

    Hello again. Sorry for all the posts. I have a histogram of frequencies in Mathematica and the intervals on the x-axis are predefined and kind of unrepresentative. I changed the bin number (with 'Histogram[mydata, binnumber]') but I can't seem to find anything on the internet about changing...
  18. S

    Mathematica Plotting Data in Mathematica | Pareto & Frequency Plots

    I have imported a list of data of this kind 4.447E-02 1.620E-02 1.281E-02 2.585E-02 3.676E-02 1.232E-01 7.635E-02 1.756E-02 1.142E-02 3.676E-02 and it goes on, 2000-ish numbers. I try to do a ParetoPlot and all I get is an empty plot. I have loaded the Statistic Plot Package. Is it...
  19. N

    Mathematica Mathematica: Function output to array

    Hello everybody! I've got a Mathematica problem that I've been working on for a while but can't seem to solve. My code is pretty involved, so I'll simplify the dilemma for you. F1 := Function[{x,m,b}, y = m*x+b; Print[y] ] I have a function called F1. If I call it like...
  20. I

    Reflecting light ray between two curves in Mathematica

    Hello everyone, I am working on trying to model a bouncing light ray between two curves, and I would like to model it in Mathematica. However, I do not know what syntax or how to go about typing the code in. I tried to find examples on the Mathematica Documentation Centre but the examples...
  21. N

    Test for Eulerian Paths in Mathematica

    Does anyone know how to test if some graph contains an Eulerian path in Wolfram Mathematica? I don't need the actual path, I just need to know if one exists.
  22. A

    Mathematica Mathematica graphing problem - twisted plane

    Hi folks, I'm trying to graph something in Mathematica, and honestly don't know where to start. Imagine you have a rectangle in the x,z plane of a 3D space. Now, twist one end of the rectange so it's parallel to the y axis. The opposite end remains parallel to the x axis. Between the two...
  23. Saladsamurai

    Mathematica Mathematica: Evaluate Value of Alpha & Output to Text File

    Hey folks :smile: Clearly there is a better way to do this. It should be clear that I want n to take on the value of alpha and not the expression "alpha --> value" What I really want to do is this: Evaluate the value of alpha at each value of i and then output the value of i in one...
  24. D

    Mathematica Help with Mathematica: 3D Point Definition

    Hello, 1) I am trying trying to simulate a laser scattering experiment in Mathematica. So the first trouble I have is how to define a set of 3D points. I did this program in C++ like this: for (int i=0; i<3; i++) { pyr[0].point[0][i]=0; } for (int a=1; a<3; a++) { for (int b=0; b<3...
  25. G

    Mathematica [Mathematica] Symbolic integrals simplification

    Hello everyone, I have a symbolic expression like Integrate[a*f[t],{t,0,y}] and I want Mathematica to write it as a*Integrate[f[t],{t,0,y}] i.e. whatever does not depend explicitly on t is a constant which can be factored out of the integral. How can I do this ? TIA :smile:
  26. S

    Mathematica I need a help about Mathematica

    Greetings from Turkey, Friends, I have a big problem about Math. the problem is that I have three equations having 16th orders and I got 16 amount roots which have both complex conj. and real parts by solving these equations with the code of the NSolve, up to here It is all ok, but I would...
  27. S

    Mathematica Taking only the positive sqrt in Mathematica

    As my title says, I need to take only the positive square root of some evaluation. For my calculation, the negative square root is extraneous. What I do is a normalization of a wave function: J = Integrate[Psi[x]^2, {x, 0, a}] sol = Solve[J == 1, A] A /. sol My only problem is those...
  28. G

    Mathematica [Mathematica] Baffling bug in LogLinearPlot[]

    Hello everyone, This drives me nuts… I want to plot a function using LogLinearPlot. Take a look at what's happening : http://img208.imageshack.us/img208/8346/picture4b.jpg I printed the values of the variable passed to my function because I didn't understand what happened… Although...
  29. D

    Mathematica Simplify this expression with Mathematica

    I know this expression should return a Gaussian distribution but I can't get Mathematica to simplify the integral. What am I missing? \text{Simplify}\left[\frac{\text{Product}\left[\text{PDF}\left[\text{NormalDistribution}[y,\sigma...
  30. N

    Mathematica Mathematica: Plotting piecewise functions

    Hi guys Take a look at DensityPlot[If[x == 0 && y == 0, 1, 0], {x, -1, 1}, {y, -1, 1}] This just gives me a uniform plot. Why does the peak at the origin not show up? Niles.
  31. N

    Mathematica Mathematica: Discrete Fourier Transform

    Hi all I have a function F, which depends on a discrete variable x, and I need to Fourier Transform it. I have put all the values of F in a table. Then I have used the command "Fourier" on the table, which - according to http://reference.wolfram.com/mathematica/ref/Fourier.html - results...
  32. F

    Mathematica Integration Question

    Hi, I need to find this integral: G(f)=-A\int_{\frac{-3T}{2}}^{\frac{-T}{2}}e^{-j2\pi ft}dt+A\int_{\frac{-T}{2}}^{\frac{T}{2}}e^{-j2\pi ft}dt-A\int_{\frac{T}{2}}^{\frac{3T}{2}}e^{-j2\pi ft}dt Here's the working out I did: G(f)=-A[\frac{e^{j\pi...
  33. C

    Mathematica How to Set a Variable Equal to a Constant with Zero Derivative in Mathematica?

    Hello everyone, I just started using Mathematica and was wondering how do you set a variable, such as 'A' or 'B', equal to a constant whose derivative is equal to zero. So for example if I were to input something like this: Dt[A*E^(2 x)*Cos[3 x] + B*E^(2x)*Sin[3 x], {x, 2}] it...
  34. D

    Curious Mathematica Result, Evaluating Bell Ineqality

    Hi guys, first post, sorry if it's in the wrong place. Frequent visitor, you seem to help pretty comprehensively. I'm using mathematica to calculate a bell inequality, with a general noisy quantum state. However, when I evaluate it, I get a sequence with an a in the result.. which isn't a...
  35. C

    Mathematica Homework Issue: Missing Points, Scaling Problem

    Homework Statement When I put the this code into Mathematica, it fails to plot all of the points... there are some missing points, so i decided to also tell it to display the table so I can look at the values, but some are not defined, and it puts something like y[0.95], y[0.35] or y[0.]...
  36. G

    Mathematica [Mathematica] Accuracy of a function

    Hello all :smile: I have a very complicated function, let's call if f. My problem : f[0.01] does not give the same result as f[1*^-2] because of accuracies. In the first case, the argument 0.01 has machine precision which is not sufficient in my case and the result is wrong. In the second...
  37. A

    Mathematica Surface plotting problem in Mathematica

    Hi! I would like to plot a so called breathersurface in Mathematica, but it gives a really bad picture, which I do not really want to use in my thesis: http://www.cs.elte.hu/~azo/Breathersurface.JPG" As you can see, it has holes in it, while it should not have. I used here...
  38. J

    Mathematica Generating Random Numbers in Mathematica 0-1 (2 Decimal Places)

    I want to use the random number generator in mathematica to give me numbers in the range of 0 to 1, but only to two decimal places. Can anyone help? Thanks.
  39. G

    Mathematica Solving a complex equation involving conjugates with Mathematica

    How can one obtain (using Mathematica) all the solutions of an equation involving conjugates like for example z \bar{z}=1. Although this equation is very simple, it seems that Mathematica is not able to handle it. I obtain: Solve[z Conjugate[z] == 1, z] InverseFunction::ifun: Inverse...
  40. G

    Mathematica How to Transform a Matrix in Mathematica?

    [Mathematica] “Explose” a matrix Hi all, Sorry for the title :biggrin: Here is what I need to do : Transform this matrix (sorry, didn't find the LaTeX for matrices; pmatrix does not work) a b c 0 0 0 0 0 0 d e f 0 0 0 0 0 0 g h i 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0...
  41. G

    Mathematica Mathematica issue: Skip a loop step in Table

    Hi everyone, I have to do a list made of evaluations of a certain function, but if some condition is not satisfied, then I don't want to have the corresponding evaluation in my list. So I tried: Flatten[Table[If[condition,f[i],{}],{i,imin,imax}]] "condition" is true or false depending...
  42. P

    Mathematica Finding the first roots of a function with Mathematica

    Hello everyone, I have just created my account here and so this is my first post and I would like to appologise if my question may have been posted by someone else. I am new to mathematica but I am very found of the program. So much so that I am trying to use it for one of my research...
  43. A

    Mathematica Can I solve a system of P.D.E's in mathematica symbolically?

    SOLVED I tried (with DSolve) but it just returned the input code, so I guess it can't. I also looked for it in the documentation center with no luck. Is there another way? By the way, I'm using mathematica 7
  44. I

    Mathematica System of equation with Mathematica: HELP

    System of equations with Mathematica: HELP Hi there. I am trying to solve a system of equations. I have written a mathematica code to solve this systems << VectorAnalysis` Kc > Ku > 0; Kuz > 0; SS = 2.5; Hfz > 0; Kc = 0.0144; Ku = Kc/3; Kuz = 5 Kc; B = 0.1; Hfz = 0.1157676*B; S =...
  45. RyanJ

    Mathematica How to Create a Prime Number Image in Mathematica?

    Hey guys! Basically I have a table of prime numbers. What is to write this table as an image - from 1 too 480000 - showing each cell that is a prime as white and the others as black. So basically I'm cycling the numbers from 1-480000 and if they are prime then I want the cell white and...
  46. N

    Evaluation & visualization of double differentials in Mathematica

    Hi, I'm trying to figure out how to use: http://www.wolframalpha.com/. I would like to be able to evaluate this function with different initial values and visualize results in some way, if possible: d^2F = k/r^2 * i1*dl1 \times (i2*dl2 \times R) Evaluate and visualize: k= 5, i1=i2= 1...
  47. S

    Mathematica Simulating Normal Distribution in Mathematica: Histogram and PDF Plotting

    Hi guys, On my homework, I'm simulating a normal distribution on Mathematica by adding up a bunch of RandomReal[] , that is, uniform(0,1) random variables, and using the central limit theorem. I would like to plot both the histogram and the actual Gaussian probability density function on the...
  48. M

    Mathematica Factor multiple terms in mathematica

    Hello, I have a long equation and using Mathematica 7 I want to factor out terms such as x,y,xy, x^2y,xy^2, etc. so that I'll have it in a form similar to a + b*x + c*y + d*(xy) + e*(x^2y) + f*(xy^2) + ... I've tried using the Collect by passing {1,x,y,xy,x^2y,x y^2,...} as the terms to be...
  49. R

    Mathematica How to fit data to a function then have Mathematica mark the inflection points?

    Here's my data: data = {{0.0, 2.91}, {0.25, 2.96}, {0.4, 3.08}, {0.7, 3.18}, {1.0, 3.25}, {1.2, 3.31}, {1.4, 3.37}, {1.6, 3.45}, {1.8, 3.49}, {2.0, 3.54}, {2.5, 3.65}, {3.0, 3.74}, {3.5, 3.81}, {4.0, 3.88}, {4.5, 3.94}, {5.0, 4.0}, {5.5, 4.04}, {6.0, 4.09}, {7.0, 4.19}...
  50. S

    Mathematica Mathematica - Specific shading vs global - Mesh or ListPlot?

    Hi, I am trying to shade two portions of the polygon defined by the dotted line in this code. The Mesh and MeshFunction cmds seem to allot global shading only. What is the best tool to shade, say half of the aforementioned polygon? Function[{LtMarg, BotMarg, RtMarg, HVal, DVal, rVal}...
Back
Top