Mathematica Definition and 1000 Threads

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:

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...

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...

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...

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...

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.

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...

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...

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...

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...

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.]...

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...

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...

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.

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...

[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...

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...

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...

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

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 =...

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...

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...

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...

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}...

how much mathematics is important in astrophysics? (which topics mainly?) is astrophysics is a kind of theoretical or observation physics?

Hi, I have this problem, I need to plot the solution of the next nonlinear-PDE problem: y_{tt}=((y_x)^3)_x+y^3-y where y=y(x,t), and we are looking for a solution with a compact support in (-x0,x0) (which I need to find x0), i.e the solution vanishes for x>=x0 or x<=-x0, and also y=y_x=0 on...

Hi everybody: I'm trying to analyse equations of analogue electronic filters, but i can't get the "norm" of the complex polynom if i use variables (or symbols? what's the difference?), here's the simplest exemple (RC low pass filter, a represents R*C*w, reals variables > 0): Assuming[ a...

Hello, I have the following code in Mathematica: G[k_, l_] := MatrixForm[Table[If[i == j, 1, 0], {i, 1, 3}, {j, 1, 3}]]; Print[\!\( \*UnderoverscriptBox[\(\[Sum]\), \(k = 1\), \(3\)]\( \*UnderoverscriptBox[\(\[Sum]\), \(l = 1\), \(3\)]Det[G[k, l]]\)\)]; but it does not...

Is there any way to make Mathematica display the variable name in the output? For example, if I have the following: In[1]:= A = 1 + 2 + 3 By default Mathematica outputs this: Out[1]:= 6 I would like it to instead output something like this: Out[1]:= A = 6 Or in some other way...

On web where I can find interesting samples, math, physics or nature simulations like this o: http://demonstrations.wolfram.com/"

Hi, I am currently dealing with really huge (~ 80,000 x 80,000) sparse matrices. I this context I need to read the number of non-default values in each row. When Accessing the i-th row of a SparseArray, this information is given. E.g. test = SparseArray[{{1, 1} -> 3, {1, 5} -> 2, {5, 3} ->...

I am looking to invest some time into learning one of these programs, higher math and physics, can someone contrast and compare these programs, strengths/weaknesses etc?

Hey folks :smile: I just got my student copy of Mathematica 7 and I am really excited to get started. I have some MATLAB m-files that I want to replicate in Mathematica to help me get the syntax. I am a little confused as to where to start writing it though... In MATLAB, you can write...

Homework Statement I need to solve the Schroedinger equation (Using DSolve in Mathematica) for a potential that is infinite below z=0 and V=mgz for positive z. Homework Equations TISE: \psi \text{''}[z]+\frac{2 m}{\hbar }(\text{En}-V[z])\psi [z]==0 The Attempt at a Solution...

I have an integration to perform \sqrt{\text{E1}^2-m^2} Log\left( \frac{m^2-m_B E1-m_B\sqrt{E1^2-m^2}}{m^2-m_B E1+m_B \sqrt{E1^2-m^2}}\right) Sqrt[E1^2 - m^2] log((m^2 - mB (Sqrt[E1^2 - m^2] + E1))/( mB (Sqrt[E1^2 - m^2] - E1) + m^2)) over the region {E1,m,mB/2} E1 is the variable. m is...

Hey all, I'm trying to solve a PDE in mathematica of this form: d^2 f / dx^2 = df/dt + f where f is a function of x and t. So I input this: DSolve[D[V[x, t], {x, 2}] == V[x, t] + D[V[x, t], {t, 1}], V[x, t], {x, t}] does anyone know why no answer shows up? thanks.

I have to fit a resonance curve to my data points, where the equation for the curve and the data points are: model = a/Sqrt[4 k w^2 + (v^2 - w^2)^2] data = {{242, 7/10}, {244.3`, 1}, {245.33`, 3/2}, {245.54`, 2}, {248.63`, 4}, {249.6`, 5}, {250.48`, 34/5}, {250.91`, 8}, {251.18`...

I want to plot inverse function using Mathematica In[1]:=f = Solve[x == a * Log[y/100], y] Out[2] = {{y -> 100 E^(x/a)}} and then? how to use this reult to plot? ThanksAnother question is about the axeslabel, when I set the Frame->True, the AxesLabel can not be displayed correctly, where...

I want to find the maximum of the total of a list of numbers, of which each depends on some variable x. I'm taking the discrete Fourier transform of a set of points of a function, and trying to maximise the sum of the resulting list. Although I can plot the sum of the list as a function of x...

Hi, can anyone tell me, how to make the lines in a legend more legible (or larger)? When I am making a legend, the colored lines are too faint, so that I can't see what they refer to. Thank you, Juliane

Does anyone know how to plot noise in mathematica? I want to plot a normal distribution which is white noise in the time domain. This is because I want a constant power spectral density but Gaussian spread of values. Anyway I can plot a list of normal distributed numbers but want to know how to...

Homework Statement I am trying to find Rydberg's constant. I took measurements using a spectroscope and now I want to do a NonLinearModelFit on the following function: \theta = \theta_0 + \alpha + \Arcsin{p k - \Sin{\alpha}} Where p is 1/(d*Rh). I know d and so I can calculate R_H if I...

Hi Guys, I'm trying to solve a system of differential equations using the Dsolve function of mathematica. The run is taking too much time without giving any results (2 or 3 days)... does that mean that there's something wrong in my equations? or that mathematica is unable to solve it? or is it...

Hi there, Making a nice visual for a quantum problem, which is finding the probability of finding the object outside of the classically allowed region for n=0,1,2. One problem: How do I make the y-axis stop after the origin so it doesn't mess up my arrows or my text (see attached)? Any...

I need to multiply 2 matrix in Mathematica but modulus an Integer. The "Modulus->n" option cannot be used with "Dot" function. You can use Modulus-> n with "Inverse" or even "Det" but not with "Dot". It is something strange. How should I do it, then? Any idea? Thank you.

Mathematica to use it! Hey guys I was wondering if there a way to read the variable parameter in Manipulate outside the manipulate , what i mean 4 example : Manipulate[ Plot[am E^(-(x - c)^2/(2 sigma^2)) , {x, 0.004, 0.00415}], {sigma, 0.00001, 0.00015}, {c, 0.0040754, 0.00415}, {am, 1...

I am trying to iterate a solution to a non-linear differential equation - but I am unable to evaluate a statement within a Do loop Code: Do[q = Cos[Evaluate[x'[i]/.up]]; If[ q <= 1, Print[q], Print[i], Print[i^2]], {i, 0.1, 1, .1}] x'[i] is a solution to NDSolve The output is i^2, which is...

Disagreement between Mathematica 5, 6 and 7! ?? Hey I've got a piece of Mathematica code which I'm working on that appears to behave differently depending on which version of Mathematica it's run on... I've tried it on versions 5, 6 and 7 and running the exact same program with the exact...

Hy Guys I want to create some lines. That lines should be created by the solution of an equation. This equation has in my limits 1 or 2 solutions. The first euation is a circle. The second is a line. lineslope, radius, lineshift1, lineshift2 is defined before. sol = Table[ NSolve[{radius^2...

Manipulate Mathematica! Hey guys I have a data imported as List, i plotted this data as ListPlot, i need to fit this function with gaussian, the standard fit or find fit or nonlinearmodelfit didn't work, so i used Manipulate as : Manipulate[ Plot[1/(sigma Sqrt[2 \[Pi]]) E^(-(x - c)^2/(2...