# All Questions

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2 views

### Split String after a Character

I want to split strings after "." a = {"this si theh jnfdkdkvd/. and then this is . and then this is. \ gjgjdjd. ugddjgd. ddngdjng."} in ...
6 views

### why did the one without Assumptions in Integrate work while the other one don't?

Here is 2 trials I have already tried. Assumptions in Integrate. Input: ...
17 views

### Last part of a url (after the “/”)

I want the last number after the "/". How can I do that? "http://arxiv.org/abs/math/0208009v1" I just want 0208009v1 I want to import multiple ...
23 views

### Why are nested anonymous pure functions shielded from evaluation?

I tried the following code (ignoring the warning messages): ...
23 views

### Confusion about the sorting function

The following one-dimensional array can be sorted well: Sort[{Infinity, 10, 2, 1, -4}, #1 < #2 &] But the following two-dimensional array cannot sort the <...
10 views

### Asymptotic Relation as Boundary Condition

I want to solve a system of non-linear second order differential equations. For some of the unknown functions there are boundary conditions that i know how to write them in Mathematica. One of the ...
28 views

### How to write a more concise RowReduce function that can deal with symbolic matrix?

I wrote an RowReduce function that can handle symbolic matrices: ...
46 views

### Keep irrelevant variables outside function arguments

I want to define several functions of variables x,y say ...
68 views

### How to get the progressive application of list of rules?

all. I need some suggestion on this problem. I have a very long list of rules, using this list of rules I want to see how some elements evolve as I successively apply the next rules on the previous ...
39 views

### Why doesn't Mathematica ComplexExpand integrals?

Consider this code example: ComplexExpand[Re[Integrate[f[t], {t, a, b}]]] Mathematica gives me the result as ...
55 views

### Visualizing an Affine Matrix

I have a computer graphics program that prints out affine matrices like ...
42 views

### Plot3D lighting issue

Plot3D is giving me very weird lighting. If I run the following line of code from the Plot3D documentation. ...
18 views

### LU decomposition and power of a matrix [closed]

How to write codes of LU decomposition and power of matrix on Mathematica? Please can you tell me?
53 views

### Mass Transport FEM Using Quad Mesh

This question is a follow-up to my previous question and an attempt to implement @Tim Laska's excellent approach of setting up an anisotropic quad mesh. I'm solving a similar problem to @Tim Laska's ...
32 views

I have to calculate a 2-dimensional radially symmetric distribution from a single projection. I know that InverseRadon should actually do the job, but I get the ...
23 views

### Why are these expressions with shifted delta functions not equal?

I have the following equation Exp[a-t]*DiracDelta[t-a] == DiracDelta[t-a] which cannot be evaluated. However, if I plug in 0 for a: ...
38 views

### NDSolve and NIntegrate with parameters

I have a problem with a numeric computation. I should solve a numeric ODE and the rhs is a numeric parametric function that I find with several NIntegrate. I'd like ...
43 views

### Sorting out polynomials with roots of an undesireable magnitude

I have a list of polynomials polys. I want a set of $f(x) \in$ polys which have roots strictly in $\{S^1,0\}$, with $S^1$ being ...
29 views

### Is it possible to make a composite tooltip with multiple data types?

I have a large set of spectral data that requires comparison to training data. I need to provide a simple color difference for each piece of data, Spectral Plots of both the training data and RMSE ...
34 views

### Fast way using inner row-elements iteration to construct matrix?

I'm trying to construct a matrix which is according to inner last two row-elements. ...
40 views

### I need advice on which device to get to be able to run Wolfram notebook applications on the go on mobile phones?

I am planning to get a new phone later this month since I have moved to a new country and my old phone is causing me difficulties. I see there are good deals on Samsung (Android) and iPhones (IOS). My ...
39 views

### wrong syntax in very short package

Here is a very short package ...
26 views

### How to find expansion coefficients in Fourier-Legendre

I am trying to find the coefficients for the Fourier-Legendre expansion of a potential. My goal was to obtain the coefficients as expressions in terms of x and y. I followed the example given on the ...
29 views

### problem with solving a simple third order differential equation [duplicate]

I just wrote a simple line of code to solve a third-order differential equation: DSolve[{y'''[x] + 4*y[x]==0, y[0]==1, y'[0]==2, y''[0]==0}, y[x], x] Then ...
27 views

### How to optimize a function with two variables such that the constraint is satisified

I have a hollow bar with outer diameter d1 and inner diameter d2. One end of the bar is fixed and the other is subjected load. ...
56 views

### How to plot a complex functions in complex plane?

How to plot a complex equation like f(z)=z^2 in complex plane? Is it required to separate the real and imaginary parts or it can be done directly ?
18 views

### Solving system of coupled PDEs with method of lines

I'm trying to solve: $\partial _{z} U(z,t) = i \sqrt{d} P(z,t)$ $\partial _{t} P(z,t) = -P(z, t) + i \sqrt{d} U(z,t) + i \Omega_{c}(t)S(z, t)$ $\partial _{t} S(z,t) = i \Omega_{c}(t)P(z, t)$ For the ...
29 views

### Data set for Neural Network

I am using Regression with Neural Networks and I want to set my train and test dataset. But I have a huge dataset in Excel that obviously do not have the shape that Mathematica requires. If I ...
37 views

### Deriving formulas for continued fraction expansions

A version of a continued fraction expansion of a rational number $r\in \mathbb Q$ is defined as \begin{align} r =[a_0,a_1,a_2,\ldots,a_k]= a_0 - \frac{1}{a_1 - \frac{1}{a_2 - \dots - \tfrac{1}{a_k}}} \...
36 views

### I have two equation two unknowns, how to find there expression symbolically

I have a two-equation with two unknowns r2 and t. I am trying to solve for them symbolically is it possible? ...
10 views

### How to create a denominator for division in Wolfram Cloud? [duplicate]

How to create a denominator for division, or other math objects like superscript for exponent, in Wolfram Cloud? In Mathematica you have the typesetting/characters window, or you can use Ctrl+/ for ...
69 views

### Why doesn't Mathematica cancel this constant out of the integral?

I have the mathematical expression Integrate[f[r], {r, τ, t}] == a*Integrate[f[r]/a, {r, τ, t}] which is obviously true for all functions ...
32 views

### How can I make a two-dimensional plot for a complex function [closed]

How can I plot an equation involving one complex variable in the $xy$-plane (in two dimensions)? For example, consider Abs[z] <= 4 which is the region ...
30 views

### Comparing elements in a list and ignoring white space

I have two lists with element entries. I want Mathematica to identify an element in an opposing list such as Ag107 to be the same as Ag 107 ignoring any space. Each different element occurs only a ...
14 views

### A package that was found in while local directory stops being found when I move it to AddOns [closed]

I'm trying to move a package that was residing in local directory (and was found and worked) to AddOns folder. But, I get an error message ...
109 views

35 views

### Overlay for two axes plot

I have these two plots that I want to merge in order to create a plot with two axes. I just want to translate the second plot in order for them precisely coincide. However, it seems that the Translate ...
25 views

### Generating a list of the degree-$n$ Kronecker polynomials

A Kronecker polynomial is a polynomial such that Its coefficients are integers, Its roots are on the unit circle or $0$, Its leading coefficient is $1$. From here, there are finitely many Kronecker ...