Mathematica Definition and 1000 Threads

Wolfram Mathematica is a software system with built-in libraries for several areas of technical computing that allow symbolic computation, manipulating matrices, plotting functions and various types of data, implementation of algorithms, creation of user interfaces, and interfacing with programs written in other programming languages. It was conceived by Stephen Wolfram and is developed by Wolfram Research of Champaign, Illinois. The Wolfram Language is the programming language used in Mathematica.

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  1. M

    Mathematica Solve Error in Mathematica: Get Solution Here!

    Here is my code Nl = 10^(49) ; Nh = 100 ; b = 4*10^(-13) ; Rs = N[((3 Nl)/(4 Pi b Nh^2))^(1/3)]; a = 6*10^(-18) ; Solve[x/(4 Pi r^2) E^(-Nh a x) a Nl == (1 - x)^2 b Nh, x]When I run it, it shows the error: "Solve::nsmet: This system cannot be solved with the methods available to Solve. >>"...
  2. IridescentRain

    Mathematica How do I calculate an area in Mathematica?

    Hi! Say I have a region described by any number of inequalities. This region is a surface in 3D space. How can I ask Mathematica to calculate the region's area? If it helps, my particular region is the intersection of a hollow sphere and a solid (i.e. filled-out) toroid-like surface. I'm...
  3. Hepth

    Mathematica Mathematica : Pulling inputs from a function; methodology question.

    I have a heaviside function: HeavisideTheta[a,b,c,d,e,...] where the letters correspond to functions, and the number of functions is arbitrary. I want to make a replacement so that HeavisideTheta[a_]:> If[a>0,1,0] HeavisideTheta[a_,b_]:>If[a>0,1,0] If[b>0,1,0] or something similar. I wish...
  4. H

    Mathematica Mathematica NDSolve conditions help

    Hi, I'm having a problem with NDSolve in mathematica where it is interpreting my initial conditions as "True" or "False". Here is the code: soln = NDSolve[{eqn1[[1]], eqn1[[2]], x[0] == y[0] == 0, x'[0] == 1, y'[0] == 0}, {x, y}, t]; where eqn1 is determined by the following code...
  5. Safinaz

    Mathematica Mathematica ListPlot: Plotting a Continuous Graph

    Hi all, I have a function varying in mass varible as 1000 - 1500-2000, etc, I made a list of the values of this function for these values of mass but when I plot by mathimatica by ListPlot it appears some how discerte between the points I defind not a continus graph. So any help to...
  6. D

    Mathematica Mathematica: Simplifying a feedback system

    Hi, I have given a complex feedback system in z domain like: Y = 2*W2 + E W2 = z^-1/(1-z^-1) * (W1 + (1-z^-1)*W2 - 1/2*(1-z^-1)*Y) W1 = V - Y + z^-1/(1-z^-1) * 1/2 * (V - Y) where Y is the system output, V is the system input, W1 and W2 are intermediate nodes and E is an error input...
  7. N

    Mathematica Solving an algebraic-integral equation in Mathematica

    Hi, I'm trying to solve an algebraic-integral equation (I don't know if this is the proper description of this class of equations, it just seems like the least wrong way to describe them) and have run into several issues that I'll describe below, but first I'll outline the problem. I'm...
  8. A

    Mathematica Help with Mathematica Issue: Solving Nonlinear Second Order ODE

    Mathematica Issue -- Help! Hello! I am new to Mathematica and i tried to solve a non linear second order ode... The result is that nothing happens... I mean that i get as output the same line as i write in input.. For example, my problem is: (thats what i get) In[33]:= DSolve[ g - b x - c...
  9. Hepth

    Mathematica Mathematica Bug : Integrate and DiracDelta

    I have found that while these two should be the same, mathematica does not evaluate them equally. Integrate[(a + b el + c el^2) DiracDelta[u], {u, 0, 1}, {el, e1, e2}] Integrate[ Integrate[(a + b el + c el^2) DiracDelta[u], {el, e1, e2}], {u, 0, 1}] I believe the second one is correct...
  10. M

    Mathematica Mathematica: Generate Surface Equation

    Hi there, I just began using Mathematica today and I was wondering if there is a way to make the program generate an equation of a surface given a 3d array? What I need it to do is to give me an equation of the surface so that given any two variables I can find the value of the third one...
  11. E

    Mathematica Use DO loop in Plot order at mathematica 8

    Can anyone help me to in this problem? I want to use DO loop in Plot order at mathematica 8, how can I do this? I want to change one variables and see the changes in other variables in the graph, and want to plot all of my graph in one Plot order. Like this. I Uploaded my file too.
  12. F

    Mathematica Help with Mathematica? Find Dictionary Lengths & Longest Words

    Part A: Get the list of pairs of the form {language,number of words in dictionary}. Call this list Alength. What I did: lang = DictionaryLookup[All] to get all the languages. Then, Alength = {Length[DictionaryLookup[{"Finnish", All}]], Length[DictionaryLookup[{"Arabic", All}]]}...}...
  13. admbmb

    Finding Shortest Distance between two 3d Parametrized Curves

    So I have two parametrized equations for two different 3d curves: Rm(t) = (1.2*sin(2πt) + 0:3)i + t4j + 1.1cos2(2π(t + 0:2))k and R(t) = Sin(2πt)i + t3j + Cos2(2πt)k I need to figure out if these two curves come within a certain distance of each other (0.5). I cannot understand how to find...
  14. G

    What is causing the NMinimize error in my Mathematica calculation?

    What wrong with my calculation.the problem is from the attachment. It keeps saying: NMinimize::nnum: "The function value {10721.1} is not a number at {rs,x} = {1.91862,1.66351}. " My code: XDDO154[x_, rs_] := Sum[(DDO154vobs[[i]] - Sqrt[(4 Pi*(43.040600502)*x*...
  15. S

    Mathematica: Illustrate a 3D vector field

    Homework Statement Hi, Firstly, let me apologize if this is not exactly the right topic to ask this questions. But since it is homework and since most of the Physicists for sure illustrate a 3D vector field, I decided to post it here. Attached I have two files with 3D vectors. How does...
  16. J

    Poincaré Sections of the double pendulum with Mathematica

    I need to plot a Poincaré map for a double pendulum where the string connecting one mass to the other is elastic with elasticity constant k and rest length s. The equations of motions are: \dot{\theta}_1= \frac{p_{\theta_1}}{m_1 r_1^2} - \frac{p_{\theta_2}}{m_1 r_1 r_2} \cos{(\theta _1-...
  17. Q

    Mathematica 5.0 notebook does not work in Mathematica 9.0

    1. I have managed to find the following notebook that would prove useful for me in calculating the concurrence of a 2-qubit state. http://library.wolfram.com/infocenter/MathSource/6227/ 2. The problem is that the code is for Mathematica 5.0, and try as I may, I could not make it...
  18. adjacent

    [Mathematica] Multiples of 5 from 0 to 100

    I have downloaded Mathematica to see if it is really that good. Many people use it. I want to calculate the multiples of 5 from 0 to 100. This seems pretty simple but I can't figure out a way to do it. I can't use the Modulo % in mathematica. I know that I should use Table. Is there any...
  19. Q

    Switching the position of matrix elements in Mathematica

    Say I have the following matrix, written in Mathematica A := {{a11, a12, a13, a14}, {a21, a22, a23, a24}, {a31, a32, a33, a34}, {a41, a42, a43, a44}} I want to exchange the positions of a12 and a21, a14 and a23, a32 and a41 , a34 and a43. Any ideas? Thanks.
  20. ChrisVer

    Evaluating Integral with Mathematica: A & B Cases

    Could someone please help me evaluate the integral with mathematica \int \frac{dx}{(a(1+x^{-1})+b(1+x^{2})-1)^{1/2}} For better in your code the integral must be: 1/sqrt[a(1+(1/x))+b(1+x^(2))-1] For a≤1 and for cases: A)0<b<1 B)b>1 I am sorry,but I haven't been able to receive mathematica...
  21. E

    Graphing Infinite Series (Mathematica)

    Homework Statement I just have to graph this function to see where the "Gibbs phenomenon" occurs in its Fourier Series representation. I am pretty sure I integrated correctly.Homework Equations Fourier Series The Attempt at a Solution...
  22. Q

    Defining variables in mathematica

    I need to define some "general" variables in Mathematica 8, and I wonder if this can be done the following way. Say ta[n] and tb[m] are my variables, in turn depending on n and m. I want to define a function, for example E[ta[n]_ , tb[m]_ ] := Cos[ ta[n] ] + Sin [tb[m] ] (just a simple...
  23. T

    Need Help Solving Problems in Mathematica

    How do I graph f(x)=x^5-x & g(x)=2 on the same x-y system and zoom into find the crossing points of these 2 functions? how do I find the terminal velocity(t->infinity) and find 98% of its terminal velocity? 1st step. take the derivative v=24.61(1-(0.27300^t) then I graph it. but how to...
  24. Q

    Mathematica indices as variables

    1. I'll post here a simplified version of my problem Say you have a matrix A, and you want all its components to be functions, for example: A11 = Sin(a_n) A12 = Cos(a_n) A21 = Sin(b_n) A22 = Cos(b_n) And I want to be able to do this in mathematica so as to have the matrix A a...
  25. R

    What are the unknown functions and variables in this Mathematica program?

    Hello Mr Bill, Sorry again If I distrubed you ,but i really need your help in solving my Mathematica program , I wrote the explanation of my job in the PDF in details ,may that help you to understand what Iam looking for ,and thank you again of your help.
  26. C

    Trouble with Kramers-Kronig in Mathematica?

    I am having trouble with one of my simulation of normal reflectance experiment. so I simulated my reflectivity as a lorentzian peak and I want to find the dielectric function ultimately. so of course the reflectivity and phase is related through kramers kronig which can then be used to...
  27. R

    Help with Mathematica Problem Solving

    Hello,I have a problem in writing my code in Mathematica, when I put values of R,T,S&a the system worked and gave me result but when I put the system in for loop , it gave me errors,I hope someone help me and thank you
  28. T

    Plotting with Mathematica or Wolframalpha

    Apologies if this is readily available, but I can't seem to find an example of it. How do I go about plotting multiple functions on the same graph? It keeps splitting my functions up into separate graphs. Nothing complicated, just something like two planes intersecting.
  29. H

    [Wolfram Mathematica] - how scripts work in Mathematica

    [Wolfram Mathematica] -- how scripts work in Mathematica Hi. This is not a homework. I just did a script in Octave and I've just finished writing it on Wolfram Mathematica. The problem is that I don't know how to define the function, I don't know how scripts work in Mathematica. My script...
  30. S

    Plotting Complex functions in Mathematica

    In a few of my books on Complex variables they show how you can look at a complex function as essentially a mapping from what plane to another. Does anyone know if there would be a way to have mathematica plot how a complex function would transform one plane into the other? Thanks for any...
  31. N

    Plot the plane x+z=0 in mathematica

    How do I plot the plane x+z=0 in mathematica on the xyz plane
  32. H

    [Wolfram Mathematica] Using Newton's method to solve non-linear system

    Hi. This is not actually not part of the homework; but it's something I'd like to do. I have to solve the following system using Newton-Raphson's method: $$\begin{matrix} \frac{X}{\mu }+Y=1 \\ X=\left( \lambda -\left( K-1 \right)X \right)Y \\ \end{matrix}$$ Surfing the...
  33. R

    Mathematica Help with Mathematica: Solve Firstresult Problem

    Hello, I want somebody help me in Mathematica My code that I wrote most of it is right ,the two first function are correct ( templet & Bisection)but the problem I faced when I wrote the function (firstresult) when I wrote in it the for loop and the if conditions the errors start to appear so...
  34. R

    How to call a built function in mathematica

    Hello,I need somebody to help me in Mathematica programm I wrote code that works as a function which I can call when I need in another function, but it did not work ,so I need help how to call my function and thanks in advance
  35. R

    How to Use FindRoot for Determinant with Fixed Values?

    Hello, I need someone to help me with mathematica my aim in the code I wrote is to find the value of "w" with fixed values of "a" and "z" which makes the determante det =0 so I need bisection method to find the value of w ,then I thought to use FindRoot function but it did not work. So how to...
  36. T

    Magnetic field from a coil (on Mathematica)

    Hello guys, I'm trying to find the configuration of two circular coils in a configuration similar to Helmholtz coils that would homogenize the magnetic field best at a volume between them. So the first thing step I took in that is use the Biot-Savart law to calculate the magnetic field...
  37. S

    Finding Non-trivial solutions to ODE in Mathematica

    For an ODE of order 2 like: X'' + λ*X = 0, how do I find the non-trivial solution in Mathematica 8? It's giving me only the trivial solution. In: ComplexExpand [DSolve[{u''[x] + \[Lambda]^2 u[x] == 0, u[0] == 0, u[a] == 0}, u[x], x]] and the out: u[x]--> 0 which is the trivial soln...
  38. moudas

    Sigularity problem in NDSolve in mathematica

    sigularity problem in "NDSolve" in mathematica Hi, I am trying to solve numerically 13 differential equations with intial boundary conditions in mathematica. In my case, the boundary conditions are not free parameters and those are constrained from experimental observations. But these set...
  39. M

    Mathematica Mathematica derivation Question

    I'm trying to work through a derivation and am getting some funny results. For example, when trying to compare some expressions, Mathematica was telling me they weren't equal, and when I worked them out by hand, I new they were equal. I then tried something like this: ExpandAll[x] ===...
  40. Sneakatone

    How to make a mathematica code with vectors and magnitude

    Homework Statement Create a mathematica code to add arbitrary number of 3 dimensional vectors. 1. n: the number of vectors which must be added 2. For each input vector, the code should accept the following: a. Length of the vector b. Three angles which the vector makes with x, y, and z...
  41. Q

    Mathematica Problem in reporting contour plot mathematica

    Dear friends I plot a Contour plot from a function with mathematica, but I don't know how can I add a small box near my figure that explain which value refer to which color? I put my code below, please help me with adding colordata to my code for having reference for colors. t = 0.01...
  42. C

    Mathematica How to Create Horizontal Filling to the Y-Axis in Mathematica?

    Filling->Axis command makes vertical lines to the x-axis. How can I make same thing for the y-axis? (Horizontal lines to the y-axis)
  43. R

    Mathematica I have a problem with mathematica

    I wrote this programm in mathematica but I had some errors that I could not solved I hope that anybody could help me For [a = 0, a <= 30, a = a + 10, For[z = 3.7, z <= 5, z = z + 0.2, For[w = 1000, w <= 20000, w = w + 1000, {m = NDSolve[{Derivative[1][y1][t] == y2[t]...
  44. Safinaz

    Mathematica - how to simplify an output formula

    Mathematica -- how to simplify an output formula Hi all, Is there any more options to simplify an out put Mathematica formula. I used //Simplify but the expression still complicated and //FullSimplify too slow and didn't work. Bests, Safinaz
  45. M

    Mathematica Using 2 color functions in a mathematica matrix plot

    I'm trying to use 2 color functions within one matrix plot in mathematica. Is this possible to do? For example, using a very simple matrix: test = Partition[Table[i, {i, 1, 9}], 3] I would like to make the even numbers vary in color increasing from white to red; and the odd numbers vary...
  46. 8

    Mathematica Mathematica, Plot Implicit function contain Sum (sigma)

    Dear friends, Over the past week, I tried to plot implicit function by mathematica but failed. I am very disappointed. Hopefully someone help me at this time. My equation is given by (see below figure): Where z0 := 6 d := 12 k := 11800 w0 := 0.025 w[z_] := sqrt[w0^2*(1 + (z/z0)^2)]...
  47. J

    Mathematica Mathematica: Trouble accurately integrating highly-nonlinear DE

    Hi, I'd like to numerically solve the IVP: x^2 y y''+2x y y'+2 y^2+xy'-x^2 y^3-(x y')^2-y=0,\quad y(x_0)=1,y'(x_0)=0 around the unit circle, x=e^{it}. When I attempt to solve it around the entire circle, I think the integration is veering of course. I believe the solution is single-valued...
  48. G

    Is mathematica wrong about this integral?

    When I type in this integral into Mathematica: $$\int_1^\infty \int_1^\infty \frac{dxdy}{(x+y^2)^2}$$ using a large number like 1020 instead of ∞, Mathematica gives me 0.785398. No matter what large number I use, Mathematica always gives me around that value. However, doing the integral by...
  49. A

    Mathematica How Can I Fix My Mathematica Animation Code for Propagator Integration?

    Hello! I need some help in Mathematica, because I'm newbie in using this program. I've a kernel for a propagator, what i want to integrate numerically by p (because the problem hasn't got analitical solution) to receive the propagator. Next i want to use that propagator for an initial...
  50. N

    Mathematica Solving trig equation Mathematica repeats results

    I am new to Mathematica and I'm not sure if I'm using it properly but sometimes the output doesn't make sense to me. I Hope someone can help me understand or correct my usage. When solving trig equations Mathematica's Solve[] function gives the correct list of solutions but some of the...
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