Most active questions
99 questions from the last 30 days
12
votes
4
answers
547
views
Recursive anonymous functions with |-> notation
We can define anonymous functions like this:
#^2+#+1 &
or like this
x |-> x^2+x+1
When we want to define a recursive ...
- 533
2
votes
5
answers
213
views
How can I generate the $z^2$ grid-mapping diagram (rectangular grid → curved grid)?
I would like to generate a diagram in Mathematica showing how the mapping
\begin{equation}
w = z^2
\end{equation}
transforms a rectangular grid in the complex $z$-plane into a curved grid in the $w$-...
- 867
17
votes
1
answer
628
views
How are people using the Notebook Assistant and how useful is it?
This is more of a community question than an answerable problem. If it's out of bounds I'll be happy to withdraw it. But, one year out, I'm curious as to other WL users' experiences with the ...
- 667
5
votes
3
answers
292
views
Is there an equivalent of Exponent for difference equations?
[Edited.]
For $ax^{2}+bx+c$, I can write
poly = a x^2 + b x + c;
Exponent[poly, x]
and get back 2.
I don't see a built-in ...
- 667
2
votes
3
answers
227
views
In a nested, ragged list, pairing each element of one sublist with each element of another
This may be a silly question, and if it is, I'm willing to withdraw it. I have a list of lists myInitialList. I wish to write a function to transform ...
- 10.6k
5
votes
3
answers
436
views
How to define a matrix to be positive definite and symmetric?
I'm somewhat new to Mathematica and want to check symbolic solutions to small positive definite symmetric matrices (like 3x3 in size), which I think should in general yield a symbolic solution since ...
- 159
3
votes
3
answers
247
views
1
vote
2
answers
339
views
Creating a spiral
This is both a math question and a Mathematica question. I am trying to draw a simple spiral, and found this diagram that fits what I am trying to create.
Implementing the math, using Mathematica, I'...
- 3,830
6
votes
2
answers
222
views
How to specify Showcase styling
I generated a mesh region and noticed in the notebook image pull-down menu the option for
"Showcase styling." How can I request this styling (gold sphere vertices, silver tube edges) for ...
- 4,855
4
votes
2
answers
294
views
Mathematica does not give me any contour here
I would like to have an idea what kind of curbe is being formed from the intersection of the plane $x+y+z=9$ with the surface
$\sqrt{16-x^2}+\sqrt{25-y^2}+\sqrt{36-z^2}=12$ under the restriction $x,y,...
- 634
1
vote
3
answers
419
views
How to change the color of the individual squares on a chessboard?
The code I have written to create a chessboard is as follows:
...
- 21
7
votes
1
answer
206
views
Feature Extractor for Molecules
Running FeatureSpacePlot[mols] gives me an interesting plot and I would like to understand the method.
Does anyone know or can point me to a reference page on how ...
- 931
3
votes
2
answers
226
views
Solving a coupled 2nd order differential equation numerically using NDSolve
I would like to solve the following system of differential equations numerically for two one-dimensional functions $R(x)$ and $\phi(x)$:
\begin{eqnarray}
c_1 \left(R''(x) - (\phi'(x))^2 R(x) \right) - ...
- 93
6
votes
1
answer
234
views
Is it valid for DSolve to return Indeterminate as a solution to a differential equation?
In V 14.3
Quit[]
ode=2*y[x]*D[y[x],{x,2}]==1+D[y[x],x]^2;
DSolve[ode,y[x],x,IncludeSingularSolutions->True]
Gives
Is it valid for DSolve to return ...
- 156k
4
votes
2
answers
139
views
Matching an expression in Hold
Trying to replace some of the expressions wrapped by Hold as below to get $\frac{k d\theta }{dt}$, ReplaceAll does not replacing ...
- 1,484