Mathematica Definition and 1000 Threads

Hi! Here is the code in Mathematica 7. sphere = RegionPlot3D[(x^2 + y^2 + z^2 <= 1) && (x < 0 || y < 0 || z < 0), {x, -1, 1}, {y, -1, 1}, {z, -1, 1}, Mesh -> False, Boxed -> False, Axes -> True, AxesOrigin -> {0, 0, 0}, AxesLabel -> {X, y, Z}, PlotPoints -> 50...

Hi! I am plotting the following in Mathematica 7. RegionPlot3D[(x^2 + y^2 + z^2 <= 1) && (x < 0 || y > 0 || z < 0), {x, -1, 1}, {y, -1, 1}, {z, -1, 1}, ColorFunction -> Function[{x, y, z}, ColorData["TemperatureMap"][x^2 + y^2 + z^2]], PlotPoints -> 50, Mesh -> False...

Good day to all, I'm trying to construct a m x m (size) matrix which have 1/2 on the diagonal, zeros to the lower triangular and 1 to the upper triangular. m=10; f[i_,j_]:=1/2 /i==j f[i_,j_]:=1 /i>=j f[i_,j_]:=0 /i<j m=Array[f,{m,m}]; m //MatrixForm I think, supposedly this will...

Given a power spectral density Sn(f) (or alternatively the autocorrelation function), is there a way to output random noise in Mathematica? Not sure if anyone here will know this but it's worth a try.

I have an interpolating function in mathematica and just want to find when it takes a certain value, seems simple, but I can't do it. i.e. I solved an equation numerically for z(rho) and got interpolating function x for z. Now I want to know for which value of rho, z(rho)=1 for example...

Hi I intend to use a interactive program I have written in mathematica in a presentation. But it has become apparent that I may not have internet access when giving this talk, my license only allows me to open mathematica when I am connected to the web. Is there any programs that will allow...

Good day to all, I need help on how to change font size for numbers in x and y axis. For axes label I could change the font size using below command, but how about the scaling itself. Plot[Sin[x],{x,0,100},AxesLabel->{Style["t",Italic,Large]}] Thank you in advance. Regards, sugaku

Hi all I'm am looking for a smart way to make the following conditional in Mathematica: if[i == 3*{1,2,3,4,5,N}, ...], ï.e. if the variable i is a multiple of 3 up to some integer N. How can I do this smartest in Mathematica? Niles.

I have some data in a text file. I want to import this data into Mathematica, and then I want to calculate the numerical derivatives of this data. In particular, I need to find the y value where the first derivative is equal to zero. I can import data. I can use the ND function for numerical...

Good day to all, 1) I find difficulty on putting two 2D graphs into one figure. If same command it is easy to do but i have different commands, the commands are listlineplot and plot...

I have a function which depends on several physical constants, which I want to be able to vary each time I make a plot. What is the best way to do this?

I just got Mathematica last night and am trying to use it for the first time. I'm trying to plot a graph f(x)=K(1-x)^{\frac{-3}{8}} but it's not working right. I tried first with K = 325 (for physical reasons) and the graph started negative at x=0. If I choose K to be almost anything other...

DSolve[{x'[t] == (\[Alpha] - (x[t] - 1)^2) x[t], x[0] == 0.004}, x[t], t] I get the following message: Solve::tdep: The equations appear to involve the variables to be solved for in an essentially non-algebraic way. >> DSolve::bvnul: For some branches of the general solution, the...

Hi, I ran this program: P = Table[Subscript[p, i, j], {i, 0, 3}, {j, 0, 2}] For[j = 0; i=0, j <= 2, j++, Subscript[p, i, j] = 2] MatrixForm[P] What is gives me is this: 2 2 2 p[1,0] p[1,1] p[1,2] p[2,0] p[2,1] p[2,2] p[3,0] p[3,1] p[3,2] If I change the...

I want to generate the following plot in Mathematica in red color: x[t_] := 31 Cos[t] - 7 Cos[31 t/7]; y[t_] := 31 Sin[t] - 7 Sin[31 t/7]; ParametricPlot[{x[t], y[t]}, {t, 0, 19 \[Pi]}] The above code creates the plot in default black color. So, I tried using this code to make it red...

I can't come up with the code to solve for a and b in terms of x and y. x + I y = Sqrt[a + I b] In[84]:= Clear["Global`*"] Solve[x + I y == Sqrt[a + I b], {a, b}] During evaluation of In[84]:= Solve::svars: Equations may not give solutions for all "solve" variables. >> Out[85]=...

Hi guys , I have the next declaration in Mathematica : myfunc [lis_list] and myfync [x_,y___] what does "lis_list" means ? I know that when I want to declare a variable of a function I must write myfunc[SomeVar_] with one _ but what are 3 times _ (meaning ___) I hope...

Hi , I'm trying to write down the following function : sort[list_] it needs to sort a list of numbers by checking each two adjacent numbers and swap them if it is needed , but it doesn't work . I need to implement it using Pattern Matching . but I don't understand how can I...

Hi , I'm trying to solve the following equation: e^x=x^3 + x^2 -1/4* x -4 using this code : NSolve[Exp[x] = x^3 + x^2 - 0.25 * x - 4, x] but it doesn't work . In addition I'm trying to solve it graphically by plotting the left and right functions simultaneously . but how ? with...

Hi- I TA two lab sections, for which I need to have different partners for every student throughout the term. It's sort of a headache to do this by hand and it seemed like the Mathematica list function should be able to do this in a snap; but I'm having trouble writing the rules and syntax I...

Hi all, There's a mathematica package called EinS... it's used for tensor calculations... has anybody of you tried it before? Is it useful? Do you have any idea how I could get it? Thank you in advance.

I'm an occassional Mathematica user (Ver 7.0.1.0). I'm doing something now where I need to import a couple of large Excel files, no problem with that. I'm wondering, however, if there is a procedure to make the resulting lists created by the imported data permanent so that I don't have to...

I'm good in writing functions in Matlab , however since moving to Mathematica , I find it pretty hard to write them . For instance I need to write a function that returns a [1,0,-1] to integers, meaning x>0 , x==0 , x<0 with a single If , but I didn't find a way with one (only two)...

Hi guys , I'm a little new with Mathematica and I'm trying to write down some functions. the first one is writing a functions that square the elements in a vector , recursively , using patterns . so , I tried this one : x = Range[1, 10]; sq[0,list_]=list^2; sq[sum_,list_] :=...

Hi, I found this mathematica packages file and can't use it... "The "FixedTalbotNumericalLaplaceInversion.m" file should be placed into the AddOns folder on the user's computer" As written in the file, i need to save this file under AddOns folder. Done with that and yet still couldn't...

I couldn't find list of functions or operators. My naive approch was to list the elements of Symbol as Symbol seems to be the Head of all functions--but this didn't work. Is there a way for Mathematica to generate this?

Hi, I'm currently in Physics graduate school, so I don't know much about mathematical logic. I got through an undergraduate degree in physics + maths. But I'm not entirely satisfied with my math, ever since I did the course on set theory. I want that kind of rigor in all the mathematical...

Help urgently needed in Mathematica Simplify Dear All, I have a very longe expression (see file attached ) of variables x, a, Lambda... etc, when I apply "Simplify" I am left only with very short expression ONLY with variable Lambda. But if in the initial expression I declare...

Homework Statement Simplify to a certain extent, as much as possible (factorized form would be best)...

How to do this in Mathematica?? Hi - I am an engineering student who is quite new to Mathematica (v. 6) but I really enjoy it. Lots of examples, easy to just play and figure out how to do something for yourself. Makes beautiful output. However, I have not been able to figure this out... I...

I have 2 parameters, p and q. rmin depends on p and q in a complex way, but for a given p and q it can be solved for numerically. I have three functions L(p,q,rmin) Theta(p,q,rmin) S(p,q,rmin) What I want to do is to plot S against L for a set of the values p,q for which Theta is...

I have a function, S[q] which is obtained by integrating another function, A[r,q] over r. My problem is that the lower limit of integration, rmin depends on q in a complicated manner. Mathematica can however solve this equation to give several routes, only one of which is real which is the...

So I want to draw a number of objects on the same picture. The object is defined parametrically: ParametricPlot3D[{Cos[u] Sin[v], Sin[u] Sin[v], Cos[v]}, {u,0,2Pi,Pi/20},{v,0,Pi,Pi/12}, Axes->None, Boxed->False] gives one object. Then Do[ParametricPlot3D[ {Cos[u] Sin[v]...

problem with mathematica - i am new to this! hi, im trying to produce a manipulate graph where the controller type is the drop down menu. (or pop up menu). However, mathematica doesn't seem to like the range of my variables. I have typed the following into mathematica: Manipulate[...

I have data in x,y pairs that I am passing to the RectangleChart function in Mathematica. But I want to be able to color each of those rectangles using a third variable z. There seems to be no easy way to do this. I can't get the ChartStyle or Style options to add this color. Anybody know of a...

Hi I have define a 3D object with ParametricPlot3D, something similar to a sphere called "obj." I then want to use a matrix, I define as "move," to translate the object around, I have been trying: obj = ParametricPlot3D... move = AffineTransform[{{1, 1, 2}, {0,1 , 1}, {0, 0, 1}}]...

Hi I've been drawing surfaces in Mathematica but some of the images come out jaggy and very unsmooth. Is there a command that can be added that will increase 'resolution' or smoothness of the surfaces. Thanks

How can I construct the phase portrait(with Mathematica) of the following system? \dot{x}(t)=y(t) \dot{y}(t)=-x^3(t)+4x(t)y(t)

Hi All, I'm thinking about buying mathematica as the student edition is pretty cheap. I would mainly need it for stuff like calculating with polynomial rings, finding generators for ideals, solving systems of polynomial equations etc. over finite fields i.e. I'm doing algebraic geometry...

Hello I imported a 30 X 30 matrix into Mathematica. I made a graph out of this and then found the minimum spanning tree. Next, I printed off a list of the edges. I included the edgeweight option to get the associated weights listed next to each edge. My goal was to ultimately sum these...

Hi I have a function that relies on n and t. I am presently drawing it with "ParametricPlot3D." I am drawing it for all t in [0,1]. Now I can either draw this for all values of n in a defined interval, say [a,b], just as I define it to draw all t. Or I can draw one value of n by using the...

Solving equations in differential topology by pen and paper, and in Microsoft word has been tedious and error prone. Can Mathematica help? Mathematica would be required to deal with tensor equations on a pseudo Riemann manifold of four dimensions with complex matrix entries. It should be...

found on http://improbable.com/2009/11/11/welcome-rejecta-mathematica/" : http://math.rejecta.org/inaugural-issue-rejecta-mathematica-released ...but waitasec, I thought there was already a journal with that name? :p http://www.math.uvic.ca/faculty/sourour/rejecta.html...

I'm trying to add a tick mark at the origin of a plot in mathematica, but seem to be having trouble. Any advice? My command looks like this right now: Plot[S[v], {v, 0, 6}, PlotRange -> All, AxesLabel -> {"Voltage", "Current"}, Ticks -> {{{6,V_th},{{0,"0"},{1,I_max}}}] The tick marks at...

Hi all! This is a generic Mathematica question, which hopefully someone can help me with! :) I have a set of data points. I have an interpolating function from those points. I have a graph of that interpolation function. The graph goes like Sin^2, and has about 10 peaks. I want to have...

Hi all, here is a question for mathematica experts(or not :smile:) I have an expression of the form: -6615. y[0] + 282.72 y[0]^3 + 1.3244 y[0]^5 - 0.002624 y[0]^7 - 178.28 y[1] + 152.912 y[0]^2 y[1]-((1309.5 y[0]^3 y[1]^4)/(y[0]^2 + y[1]^2)^4)... and I want to transfer this expression to...

Hi everybody, Last time I was here I was asking about finding roots but many things have progressed. Anyway I have another problem now. I have a linear system of equations which I'd like to solve: A.X==B And I tried two things: get the inverse of A and multiply it with B and also use...

Hello, I have an equation that when I wrote using Mathematica to get results, the results were wrong in some places. This has nothing to do with the code, which is a 100% correct code. It is a presicion issue. But when I increased the precision, say up to 20, even to 10, the code takes a lot...

Can someone pls explain hot to compute a taylor expansion for f(x,y) using mathematica

Please Help! Mathematica ignoring variable domains I had to calculate an integral, which involves real as well complex parts. As mathematica takes all variables to be complex by default I used the elements function to define that certain variables were Reals. But it doesn't change the...