Linked Questions

499
votes
37answers
115k views

What are the most common pitfalls awaiting new users?

As you may already know, Mathematica is a wonderful piece of software. However, it has a few characteristics that tend to confuse new (and sometimes not-so-new) users. That can be clearly seen from ...
19
votes
8answers
2k views

How to Set parts of indexed lists?

I would like to assign a list to an indexed variable and then change it using Part and Set like this: ...
7
votes
5answers
558 views

Defining indefinitely many functions

Is it possible to define a class of indefinitely many functions f1, f2, f3, ... such that <...
14
votes
1answer
1k views

Fittting data with combination of an unknown number of Gaussians

I have data that I want to fit with a constant plus a combination of Gaussians, with their actual number being one parameter of the fit (besides the average and the variance of every one of them). ...
2
votes
3answers
2k views

How to define constants in Mathematica like c1,c2,c3,...cn?

Manually defining the constants is tedious if the 'n' is large. how to do this?
11
votes
2answers
2k views

Solve a nonlinear PDE equation with a Neumann boundary condition

I am trying to use Mathematica 10 to solve a PDE $$u_t=u_{xx}+u_{yy}+u(1-u),$$ in the unit disk $(x,y) \in D=\{(x,y):x^2+y^2<1\}$, with the Neumann boundary condtion $$\frac{\partial u}{\partial n}...
7
votes
3answers
381 views

How to automatically define a time dependent array of a given dimension in mathematica

I am looking for a way to generate time-dependent arrays of variable dimensions in Mathematica. For example, if I want an array with 15 variables ...
0
votes
1answer
1k views

Compute the half width and full width at half maximum (HWHM / FWHM) of a mathematical expression

I have managed to compute the half width at half maximum (HWHM) and full width at half maximum (FWHM) of a sinc function through the code below. ...
1
vote
1answer
571 views

Plot 3D doesn't show anything

Good Evening, I defined a function which is composed of other several functions. Mathematica compiles well but I can't get a plot and I do not understand way. Can anyone help me with the code and ...
4
votes
1answer
302 views

How do I get Mathematica to recognize this simplification? (ReplaceAll pattern rule)

I want Mathematica to understand this $$(\sum_{k=0}^n a_k)(\sum_{j=0}^n b_j) = (\sum_{k=0}^n \sum_{j=0}^n a_k b_j)$$ I have tried this ...
1
vote
2answers
135 views

I want to plot a list of points with specified t and x[t] coordinates [closed]

I have this code: ...
2
votes
1answer
416 views

Is it possible to define several variables at once?

Is it possible, to have several variables defined in a manner similar to vars={x1, x2, x3, x4, x5, x6, x7, x8, x9, x10} and then use an expression like eg. ...
2
votes
3answers
187 views

Separating an equation into multiple equations based on coefficients

So this is similar to this. Suppose I have an equation $ax^2-bx+3a-c-2x^2+7cx+x^2=0$ I can group the terms in mathematica using ...
2
votes
3answers
131 views

How to make a list (of data points) whose name is the same as the file name from which the data is imported [duplicate]

I have a set of files, e.g. file1.dat, file2.dat,... containing data (list of data points to plot, manipulate...) I want to do the following ...
1
vote
1answer
429 views

VectorPlot3D of the Electric Field E as Determined from the Potential V

I am new to Mathematica and I am trying to create the electric field $F$ from the electric potential $V$ (using arbitrary distances) and then plot the subsequent vector graph to show that the electric ...

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