# Group Abstract

«Groups
Mathematica
The product, programming language, and integrated interactive environment called Mathematica.

# Content with tag mathematica.

### problems with re-validation

hello, if got a problem with re-validation of the activation key. In my wolfram profil, the license expiration is 24-OCT-2014. I have got an email which says to click the link below  to extend my license. But ther is no link. I wrot an email to mathematica support, but thes send me the same email....

### create 3d axis-plane

hello i  hav e 2  questions: 1)in  geogebra  i  can  create a  3d  axis and  a  plane  with  it  i  can  ''mark''  x,y  axis.also  i  can  rotate  all  this  coordinate  system.can   i do  the s ame  with  mathematica  9?is  there  any  commands  for  creating  3d  axis -plane(2d-3d)? 2)i  there ...

### How do I find x in a polynomial when x is approximate?

I have difficulty programming to find x in a polynomial. I try NSolve to set the equation to zero and solve for x. If N = 85, x= 5, and y = 17 I have an equation:y = sqrt((N * y – x^2)/x)as an approximation of the larger Prime product (or any possible product) My equation as it...

### Modeling bimodal spending patterns

I have been looking at spending patterns. The data systems I have been looking at are nearly always bi-modal. There tends to be a lot of people spending on the low and then a group of people that spend on the high end. This is an example: [img=width: 419px; height:...

### How to eliminate a trigonometric function between the equations?

Dear All, I have an equation Cos[2 x] == 0 and I want to get Mathematica to substitute the "a" for Cos[ x ] the equation should get the form 2*a^2-1==0  eqn = {Cos[2 x] == 0, Cos[ x ] == a}  Eliminate[eqn, x] doesn't work. Do anybody have any idea how to do it? Thanks!

### Mathematica won't plot my functions, not sure why?

I'm working on a project for my financial mathematics class. I have to graph 5 functions all together in one graph. Below I have a link to a screenshot as to what happens. Only one of the functions graph and another one seems to be giving an error. The rest are just blank. Please let me know what I...

### connecting ?

Hi Everyone I've transformed lists of strings to be appropriate for TradingChart  {{{YYYY, MM, DD}, {O, H, L,C,V}}......}and made some changes with a function for plotting these data: ClearAll[strzala] strzala[{{xmin_, xmax_}, {ymin_, ymax_}}, {o_, h_, l_, c_},   metoda_] := {Line[{{(xmin +...

### A tetrahedral chain challenge

In 1958 it was proved that a chain of regular tetrahedra, meeting face to face, cannot form a perfect loop: the last tetrahedron cannot equal the first, exactly. I found a loop that comes close. Picture here: [img=width: 576px; height: 448px;...

### circle and line

Hello Everyone, I had asked a question a few days ago, thanks for the answers. Now I need to improve this code. I have to draw a circle at only 24 different points like this: [mcode]x1[\[Psi]_] := Cos[\[Psi]] y1[\[Psi]_] := Sin[\[Psi]] Show[Graphics[ Table[Point[{x1[\[Psi]], y1[\[Psi]]}],...

### Chromatic polynomials for custom graphs

1 ) How to use the math functions over graphs that are not in the data graph of Mathematica? 2 ) How to compute Chromatic Poynomials for a graph introduced by myself ?

### How to include calculations in a loop (Do,Nest,Table,...others)?

Since I am not very familiar how to make calculations within a loop I look for possibilities (Do,Nest,Table,others?) for that example: Intilial t is: d[0]=7;Then: 1. Calculate aa=d[t]+2; 2. Find root of b: [mcode]b = Exp[x^2] - a == x Sqrt[\[Pi]] FRoo = FindRoot[b, {x,...

### Pattern matching - how to match on a number greater than or less than X

In the example list belowe how should I construct the pattern matching to remove any item where position 4 is greater than 20000? listX = {{m,b,24,14000},{f,b,29,14000},{m,w,72,67000},{m,b,45,84000},{m,w,67,17000},{f,w,54,4000}}; I thought it would be something like...

### Dialogs and Dynamic

Initialize global list of {string, number} pairsmain = {{"apple", 1}, {"banana", 2}, {"carrot", 3},{"donut", 4}Function to edit item number j from the listEditItem[j_] := Module[{tx, nm}, tx = main[[j]][[1]]; nm = main[[j]][[2]];[mcode] ...

### doing work on image before import

The application I am working on is taking a series of images (time lapse) and combining them into an .avi file.  That part works well.  Now I would like to superimpose on each image the date and time.  I know how to do the superimpose, but cannot figure out how to make this happen inside of the code...

### Plot the solution of numerical solution of 3 dimension on sphere surface

I have a problem in making a graph on sphere surface. I get the solution from numerical simulation and it shows the solution is written in interpolation function. let`s say the funtion is X(t,x,y,z). What I would like to do is to make a graph this function on sphere surface. Please tell me weather...

### Is Mathematica 40 times slower than Fortran with matrixes?

Consider this code: [mcode]In[1]:= ht = 0.01; In[2]:= a = Table[Sin[i] + I Cos[j], {i, 0., 0.5, 0.01}, {j, 0., 0.5, 0.01}]; In[3]:= HL = Compile[{{t, _Real}}, I ht/2*a, CompilationOptions -> {"InlineCompiledFunctions" -> True, "InlineExternalDefinitions" -> True}]; In[4]:= Table[HL[200.],...

### Difference between Clear and ClearAll, and between '* and Global`* ?

What is the difference between 'Clear' and ClearAll'  and between "`*" and "Global`*"  I have used ClearAll["Global`*"]  and values remain attached to variables.   What is the easiest way to clear all values to all variables going forward?????

### Error regarding Combinatorca

Hello... I'm new to Mathematica and just started to work  with the trial version of Mathematica.  I get an error like "Get::noopen: Cannot open DiscreteMath`Combinatorica`. >>" when I'm including

### Animation won't show moving lines, only their endpoints

Hi there, I'm working on a dynamics project modeling a trebuchet in Mathematica.  In the final output stage, I can't get my animation to actually draw the Graphics Line object properly.  It only displays the endpoints of the line.  Changing the style of the line only changes the points.  Static...

### Financial indicator

Hi Everyone How can i extract numerical values from "FinancialIndicator" plot  - for example -"UltimateOscillator" and display these values as list  ? is an option in graphic allows such thing ? Thank you for any suggestion

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