Mathematica Definition and 1000 Threads

Dear all, here is my animation of a simple plot: Animate[ ParametricPlot[ {Sin[tf], Cos[tf]}, {tf, 0, t}, PlotStyle -> {{Thickness[0.002], Red}, {Thickness[0.002], Blue}}, PlotRange -> {{-2, 2}, {-2, 2}, {-2, 2}}, AspectRatio -> Automatic], {t, 0.01, 100, 0.01}, AnimationRate -> 2...

Hi everyone: I would like to join all elements of on matrix into just one list: matrix = 1 2 3 4 5 6 7 8 9 into list = {1,2,3,4,5,6,7,8,9} Anyone has a solution for this? Thanks

Hello, I am a novice in Mathematica, but insisting to learn it. I would appreciate help in solving the following problem: (*a=1;Which[a==1,x,a==2,b]*) list := List[1611, 1612, 1613, 1614, 1615, 1616, 1617, 1618, 32, 10] For[i = 1, i < 4, i++, a = list[[i]]; Print[a]...

I'm trying to do a calculation which involves taking the derivative of a term that is millions of terms long. I'm using a supercomputer right now with Mathematica to do it but it's taking to long. Does Matlab have a faster algorithm for computing derivatives analytically?

Hi guys, I have a system of six equations and thirteen variables. I would like to reduce it to seven free parameters. I used Reduce to solve it but it is taking really long (one full day and no output yet) and I think there must be a better way. Here is my code Y = {{y1}, {y2}, {y3}} T =...

Hi, I am not really sure this is the right topic to post my question in, but it is homework so... To my data in txt file I fitted a function ##f(x)## where ##x\in [0,100]##. In the original file I had only 100 points, but now that I have a nice polynomial fit, I can get infinite number of...

If I have a function depends on for example 2 parameters f[a,b], and I know the value of this function should range between 300 < f < 400, how I know the possible ranges of the parameters in Mathematica. Bests, S.S.

I have an ODE ##e^{2x}H(Hv'(x) + H'v' + Hv'') + (k^2 - 2e^{2x}H^2(1 + \frac{H'}{2H}))v = 0## where ##H(x)## is a known function that Mathematica has stored as an interpolation from a previous ODE and ##v(x)## is the unknown function to be solved for. ##k## is the adjustable parameter. Using...

Integrate[f[qs] DiracDelta'[qs (1 - 1/x)], {qs, -\[Infinity], \[Infinity]}, Assumptions -> 0 < x < 1] Integrate[f[qs] DiracDelta'[qs - qs/x], {qs, -\[Infinity], \[Infinity]}, Assumptions -> 0 < x < 1] This is on Mathematica 8 for windows. The results differ by a sign. They are effective...

I said to Mathematica to plot a graph as this: Plot[Exp[-Sqrt[-x]] + Exp[Sqrt[-x]] - 2 == 0, {x, -10, 40}]. You can see that there is square root of -x, which should mean that the function is defined only for x<=0. But no, Mathematica would plot a curve also for positive values of x. How...

I have a function that is defined using a variety of things, some matrix algebra, some mathlink functions, etc. But they are all defined to evaluate when called with the parameters : chi2[mb, vmc, v1, v2, v3, v4, 0.1066, 0.219] gives me a number back. I can even do a table over some range...

Hello, I want to fit a two-parameter function to two points in this way: FindFit[{{0, 1}, {1, 0}}, D + C *Log[-1 + Sqrt[-C^2 + (-1 + x)^2] + x], {C, D}, x] But Mathematica won't give the values for parameters C and D. Instead it says: "FindFit::nrlnum: "The function value {0...

There is a vector ##v_i(t)## (i=1,2,3). How to define the three functions in Mathematica? What about ##t_{ij}(t,\vec{x})##? I am trying to solve my vector and tensor equtions with Mathematica. Analytical solution would be perfect but numerical solution would also be fine. Actually I am not...

Determine all three-digit number ,##N##, having the property that ##N## is divisible by 11, and ##\frac{N}{11}## is equal to the sum of the square of the digits of ##N##. This cannot be solved just by guessing. I think I should use mathematica for this,but, this sum of the digits is a scary...

So when i use the following command, I get the following error DSolve[y'[x] - y[x] == 3, y[x], x] DSolve::deqn: Equation or list of equations expected instead of False in the first argument False. >> But when i change the variable y[x] and y'[x] to s[x] and s'[x], It works why is this...

In Mathematica, I computed the integral ##\lim\limits_{n\to\infty} \frac{1}{n^2} \int\limits_{0}^{\frac{\pi}{2}} \frac{\sin((2n+1)x)}{\sinh(x)} \ dx## and it incorrectly output the answer ##-\frac{3\pi}{2}##. I wanted to try a different CAS software that might provide a different answer, but so...

Hello, I've been using mathematica the past few days and quite like it. I am trying to add some figures to my word document. Because of the size of the exported emf file from mathematica, I am unwilling to have a document that is 100MB in size. So I was searching for some ways to export...

I have an integrand with a handful of terms, and some of them have poles in the denominator of the form (x+c) (but not all). There are three poles in total, and I want to collect all the terms according to each pole individually (eg all the terms with (x-1) in the denominator, (x-5), etc.)...

If I define a function, such as f[x_, y_] := {-2 x + 2 x^2, -3 x + y + 3 x^2} I can compute the derivative with D[f[x, y], {{x, y}}] but what is the syntax for evaluating this derivative at a point?

Hello, I'm just testing out mathematica for the first time. I was hoping someone could help me make sense of this input (see attached screenshot). I'm sure I'll be running into more peculiarities as I get more comfortable with the software, Ill post them in this thread as the pop up. Help much...

Hello, I told Mathematica to do a few calculations as follows: a = 0; b = 1; n = 4; For[i = 0, i < n, i++, p = 2*x*b - 2*i*a; a = b; b = p] c = CoefficientList[p, x]; l = Length[c]; m = 0; For[i = 1, i < l + 1, i++, r = Abs[Part[c, i]]/Abs[Part[c, l]]...

Hello, I know that in Mathematica one can define a function as follows: f[x_]:=x^2. The problem is, I get a polynomial from a for loop as an expression p=a*x^n+b*x^(n-1)+... Now I want to evaluate the polynomial at a specific point. I tried to define a function from the polynomial as...

Dear every Mathematino-s in high energy physics I knew several workers in computer and mathematics, but few of them know wolfram mathematica software, so I think it is justified to let my question appear here. I use wolfram-mathematica to make 3D figures and want to use them...

Val[a_] := ToCharacterCode[ToString[a]][[1]]; GH[a].GH[b].GH[c].GH[d].GH[b] //. {GH[a_].GH[b_] :> If[Val[a] > Val[b], GH[b].GH[a], GH[a].GH[b]]} I have the noncommutative multiply of GH[a].GH[b].GH[c].GH[d].GH[b] My goal is to order these in increasing charcter value. (Val is the function...

Solve[x - 2 cos[x] == 0, {x}] this is my imput but i get an error. What is the command to solve trig functions in mathematica thanks. I searched online but no avail.

I'm trying to integrate the function Exp[-I*t*x - t^2/2] from -infinity to infinity using NIntegrate in Mathematica; the value that I get is accurate when x is small, but as x gets larger, the output from NIntegrate does not match the value I get when I use Integrate -- it gets less and less...

Hey, Say I have a function f[a,b,c] which depends on another function g[b,c] such that: f[a,b,c] = a*g[b,c] If I input, f[a,1,2], mathematica spits out a*g[1,2] rather then actually evaluating what g[1,2] is. Is there a way I can force mathematica to evaluate g[1,2] so instead, e/g if g...

Here is the code, I am using Mathematica 7 with no packages installed at the moment. $Assumptions = 0 < u <= 19/80 && I10 \[Element] Reals; FXN = Sqrt[(u - 15/16)^2 - 2/5 (u + 17/16) + 1/25] (I10 (u^2) - 1/u); PA = Integrate[FXN /. {I10 -> 1/2 Log[1/2]}, u]; PB = Integrate[FXN, u] /...

I have been using Maxima to help me review to go back to grad school for physics. I think I might be running to the limits of its functionality (or maybe I just don't know how to use it correctly). I used to have a lot of experience with Mathematica, but their license system has grown to be...

Hi, I note that in the 'more info' for NonlinearModelFit it says that it assumes the values are normally distributed around the mean response function y, which I understand is required if one wants to use maximum likelihood methods and construct confidence intervals etc. However, there appears...

I'm trying to solve this ODE R'(t)=\frac{-a}{R(t)^2} numerically in Mathematica (a, b are non-zero constants). Here's what I have: NDSolve[{R'[t]==-a/R[t]^2, R[0]==b, WhenEvent[R[t]==0, end=t; "StopIntegration"]}, R, {t,0,1}] It's returning with NDSolve:::ndnum : Encountered...

Instead of giving the results of the calculation, Mathematica says: "Tag Times in 0 × 1.52098*10^11 is Protected." as in the attached file. Anyone has any idea how to get the results?

I have a statement that looks like : vD.vD.vD.vD Where vD is noncommutative (but that doesn't really matter) I want to replace it so that each vD becomes v[a].D[a] But I would like it so the "a" is not repeating. So I need somehow a function that each time it is run returns it with...

Hello,I need help in Mathematica,my problem is that I wrote the system of differential equations and I put a certain value of the variables and it is supposed that the value of the absolute of the determent would be zero but unfortunately I did not get zero , I got another answer when I put...

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. >>"...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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.

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}]]}...}...

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...

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*...

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...

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-...