Wolfram Mathematica is a computer algebra system and programming language from Wolfram Research. Ask your Mathematica questions at http://mathematica.stackexchange.com/
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votes
0answers
11 views
Unable to find a solution for 2d nonlinear heat equation in mathematica
Please help me to find a solution in a Wolfram Mathematica program.
I have several times checked the accuracy of the entered data. They are true. The solution must exist. But a Wolfram provides ...
0
votes
1answer
19 views
Can't generate plot in Wolfram Mathematica 8
I have this function: Plot[{(sin (x)), (sin^2 x)}, {x, -2*[Pi], 3*[Pi]}]
When i'm trying to execute this function in Mathematica, i've got only this graph:
How can i set to see the lines of the ...
1
vote
2answers
47 views
Plotting a random walk using Mathematica
This is my first time posting here. I would really appreciate some help with a question from my mathematica study guide. My question is:
Suppose that a drunk randomly steps either forward, backward, ...
1
vote
1answer
17 views
Mathematica- Solve when given random variables and set equations
I'm trying to figure out if there's a way in mathematica where I can solve for particular variables when given other variables and a set of equations. Essentially there are 6 variables, and I'm given ...
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1answer
19 views
How to use NSolve or Solve with lists for variables?
I'm trying to solve this expression:
NSolve[Qforced == hFree*SA*(Tskin - T), T]
but Qforced and hFree are lists of variables but same size, ex: {1,2,3,4...};
I am getting an empty solution "{ }" ...
3
votes
1answer
43 views
How to find the best (most informative) plotting limits?
I am developing a 2D plotting program for functions of 1 variable. It is designed to be very simple so that the user should not have to select the initial plot limits (or "range").
Are there known ...
1
vote
0answers
34 views
calculate logarithm for very large numbers
I would like to calculate the following function for very large number (for example e^e^e^e^10) and would like to know the sign of the following term in general. I tried for some numbers, but it is ...
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1answer
33 views
convert valid mysql query into Mathematica statement
I have a valid mysql query:
SELECT COUNT(*), c.description
FROM name_loc f
INNER JOIN countries c ON f.fk_cnty_id = c.id
INNER JOIN identifiers i ON f.fk_ident_id = i.id
GROUP BY ...
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2answers
47 views
How to do summation to infinity in this case in maple or mathematica
maple code, no matter write this matrix in procedure or not, still get error, how to summation to infinity
DetAn:= (n)-> LinearAlgebra:-Determinant(
Matrix(
n, n,
...
0
votes
1answer
33 views
Eigenvectors with dgeev in Maxima
I am finding eigenvectors with the function dgeev in maxima and comparing them with eigenvectors I find from the same matrix but using mathematica.
In the odd column right eigenvectors in maxima are ...
0
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1answer
29 views
Issue forming function of parameters with the Cases function
This is my code so far:
k = Import["all.txt.", "Table"];
Cases[k, {name_, G_, H_, S_, Cp_, V_, a1a_, a2b_, a3c_, c1e__, c2f_,
omegalan_, cT_} /; name == "compoundname" -> {Cp, G, S}];
...
1
vote
0answers
37 views
Find the inverse of a sequence in integers in Mathematica
Let k[i] is a strictly increasing data and
A=Table[k[i],{i,1,30}];
B=List[k[1],k[3],k[4],k[7],k[10],k[12],k[17],k[18],k[19],k[23],k[26]];
Now I would like to get what is the index for B[n], ...
0
votes
1answer
18 views
Define a pdf with a unique non-null value in mathematica
I'd like to define a pdf such as:
g(x):P(x=0)=1. and P(x!=0)=0.
i.e. a pdf where the only non-zero probability occurs when x=0. Any ideas? Thanks
0
votes
1answer
27 views
Storing Values so that it prints out certain index
I have a question about storing values.
For example, if I have a list of numbers
{1,2,3,4,5,6},
how can I save that as for example, f[x] so that when I input f[0], it prints out 1, if I input ...
1
vote
1answer
28 views
Mathematica integration
guys! Sorry in advance about this.
Let's say I want to convolve two functions (f and g), a gaussian with a breit-wigner:
f[x_] := 1/(Sqrt[2 \[Pi]] \[Sigma])Exp[-(1/2) ((x - \[Mu])/\[Sigma])^2];
...
