For questions concerning the popular computational software program published by Wolfram Research. (Note: you are more likely to get quicker and more accurate response if you ask the question on their user forum or on the Mathematica StackExchange site.)

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-8
votes
2answers
59 views

Converting Mathematica code to matlab code [on hold]

I need a program to converting a long Mathematica code to matlab code because Matlab running very very very faster than Mathematica. I tested matlab.m library for Mathematica but don't work good.
0
votes
1answer
35 views

Minimizing a function in Mathematica

Edit: I simplified the function using $\textbf{Simplify[...]}$ How can I minimize this function of $x$, where $l$ is a positive constant? $$\frac{1}{2} \sqrt{\frac{x}{l}+\frac{l}{x}+4 x^2-2}$$ ...
2
votes
1answer
60 views

I can't solve this integral in Mathematica

I want to calculate the following integral in Mathematica 10 $$f(x) = ...
0
votes
0answers
26 views

Pade_Approximant in Mathematica

I want to calculate Pade_Approximant for exponential function in power of 3. I wrote this code but it seems that the answer isn't true. please help me In[131]:= PadeApproximant[Exp[x^3], {x, 0, {3, ...
1
vote
1answer
41 views

Torricelli's Law with a Sphere (Ignore Mathematica part, already solved)

Edit 1: According to this PDF, second page. The differential equation for a hemisphere becomes $$(r^2h-h^2) h' = -a^2\sqrt{2gh}$$ This differs from the equation I got, which looks like: ...
0
votes
0answers
8 views

Proving susceptibility in Lorentz Model satisy Kramers-Kronig relations

My instructor asked me to prove that the real and imaginary parts of the electric susceptibility derived from Lorentz Model satisfy the Kramers-Kronig relations using the residue theorem. The problem ...
0
votes
0answers
20 views

Simplifying expressions or expressing it in more known functions

In mathematica I asked FullSimplify[ DSolve[{y''[x] + 1/x y'[x] + y[x] (1 - 1/x^2) == x BesselJ[1, x]}, y[x], x]] and it gave as the answer {{y[x] -> BesselJ[1, x] C[1] + ...
0
votes
0answers
25 views

Ritz Approximation

I have the following problem: $1/r * d/dr(r*d \theta/dr) - N_1(\theta-\theta_a)^2 -N_2(\theta^4-\theta_a~^4)=0$ where $N_1, N_2,$ and $\theta_a$ are constants Subject to $r=1$ : $\theta=1$ $r=L$ ...
0
votes
0answers
20 views

Fifth order BVP using Daftardar Jafari method-Research paper example query?

Please check the research paper regarding numerical solution of non linear 5th and 6th order BVP using Daftardar Jafari Method (section 6: numerical results, example 1) ...
0
votes
0answers
21 views

In Mathematica, how to calculate marginal probability of continuous conditional distributions? [migrated]

I have random variables A and B, given by Beta distributions. This can be easily defined in Mathematica. I have a conditional probability P(C|A,B) which I custom-design as a function. The function ...
0
votes
0answers
26 views

Derivative with respect to a tensor in Mathematica

I am trying to differentiate a tensor with respect to another one in Mathematica but I cannot do it. Could anyone please help? The following is the code: ...
0
votes
0answers
8 views

Assign a symbolic tensor with determinant greater than zero in Mathematica

I can create a symbolic tensor in Mathematica: $Assumptions = F \[Element] Arrays[{3, 3}, Reals] Is there anyway that I can tell Mathematica, that the ...
0
votes
0answers
20 views

Solving over-identified model in Mathematica

I am having trouble with using the "Solve" function for an over identified model in Mathematica. For a just identified model, where I have as many equations as I do unknowns the "Solve" function ...
1
vote
1answer
27 views

Scaling axis on Mathematica's plots

I'm trying to get the plot below only I want the ratio y:x to be 1:1 instead of 2:1. I want the ellipse to look tall and slim instead of short and fat. Here's the code line if you want to copy and ...
1
vote
1answer
30 views

How do I plot normal distribution

If I know the range (1-24) and know the area (X), how can I plot a normal distribution so that the curve has area X?
2
votes
1answer
20 views

Generating a data set that approximates another given random variable

One of the question my friend was asked in technical interview : The probability density function for a normal random variable with μ = 0.6 and σ = 0.7:​ Below is the code to generate the ...
1
vote
1answer
26 views

Expected number of passengers for the flight

One of the interview questions that I was asked was : The small commuter plane has 30 seats. The probability that any particular passenger will not show up for a flight is 0.1, independent of ...
1
vote
2answers
41 views

How to plot a phase potrait of a system of ODEs (in Mathematica)

I am asked to use mathematica to plot the fixed-points of the following system $$ \frac{dN}{dt} = -\gamma N \left( 1 - \left( \beta M + N\right) \right) $$ $$\frac{dM}{dt} = M \left( 1 - \left( ...
0
votes
1answer
21 views

Exponential Distribution - Generate a fairly hefty data set X that is approximately exponentially distributed with μ = 0.7.

I encountered a question in one of the books, which asked to generate a fairly hefty data set X that is approximately exponentially distributed with μ = 0.7. I can do it for approximately normally ...
1
vote
0answers
36 views

ODE with Reflection

Some Background: I come from a computer science background and differential equations was not part of my course work. I'm still in contact with my professor that I ...
0
votes
1answer
54 views

how to substitute a variable by a number in wolframalpha

Peace be upon you, How can I compute \begin{align*} sin'(0) \end{align*} in Wolframalpha? like what in Maple, I try subs(diff(sin(x),x),x=0) But it doesn't ...
1
vote
0answers
15 views

Determining the sign of a function containing ratio

Problem We want to know for which values of $x,y,z,w$ the function $\sigma$ is positive or negative: \begin{equation} \sigma = \frac{A}{A^2-B^2}, \end{equation} where \begin{eqnarray} A & = ...
0
votes
1answer
20 views

Mathematica Cubic Polynomial

I am interested to find the roots of a cubic polynomial f(r)=r^2 - 2 r + Q^2 - [Alpha] r^3. \Alpha is positive real number hare, Q is real. I am interested in 2 complex roots and third root to be ...
1
vote
1answer
39 views

Analytical solution for bound state energies of infinite well

I am trying to find bound state energies assuming infinite potential. I have been told it can be done by analytically solving Right Hand Side and Left Hand Side of an equation such as: ...
3
votes
1answer
65 views

Integration: $\frac{2}{\pi} \int_0^\pi \frac{\sin(nx)}{10}x(\pi-x) \mathrm{d}x$ Can someone matlab/mathematica/maple it for me?

I want to compute $\frac{2}{\pi} \int_0^\pi \frac{\sin(nx)}{10}x(\pi-x) \mathrm{d}x$, where $n=1,2,3,4,\dots$ I worked this by hand and got the result: $-\frac{4\cos(nx)}{10n^3\pi}$ To check my ...
1
vote
1answer
68 views

Mathematica Question regarding NSolve

I'm trying to solve for 2-cycles for the equation $$x=xe^{r[1-x]}$$ using Mathematica. I've tried using NSolve, FindRoot, and Solve. When I use NSolve I input it as $$\textrm{NSolve}[xe^{r[1 - xe^{r[1 ...
0
votes
0answers
24 views

Plotting Dirichlet Series $L_{\tau}(s)$ related to Ramanujan tau function in Mathematica

According to wikipedia, Ramanujan tau function $\tau:\mathbb{N}\to\mathbb{Z}$ is defined by equating the coefficients of the power series on both sides of the identity: ...
0
votes
0answers
11 views

Introduce break after operation

I have made a function to select manually feature points in two images. However I can keep clicking endless because I don't have a limit for feature points. I now want to introduce a kind of button on ...
1
vote
1answer
63 views

Mathematica Giving Me Trouble

I'm new to mathematica and am just learning the basics. I've run into a few things that I can't figure out. The first is this: "Number 11" $$r[t\_] := \{(1/3)*(t^3), 0.5 * t^2, t\}$$ (*Unit ...
1
vote
1answer
28 views

In Mathematica is it possible to define the plot range by an inequality?

For example, like Plot[Sin[x], {x, Sin[x]<0.5}] The above line is not working. I want to know if this idea is possible in Mathematica. Thank you!
0
votes
1answer
56 views

Best program for multiplying many multivariable polynomials

I want to make a table with two columns: The first column will consist of many(possibly hundreds) of polynomials in two variables. The second column will be a function applied to all of the ...
2
votes
0answers
58 views

Algorithm to find the “optimal” path in a given graph

Assume that $G=(V,E)$ is an undirected connected graph and that $H: V \to \mathbb R$ is a function that assign at each vertex $v \in V$ its height $H(v)$. Think of the pair $(G,H)$ as an energy ...
1
vote
0answers
15 views

Assigning a variable as constant and find out the minimum value

I have got a problem in assigning a variable as constant and solving a equations for minimum value. These are my equations: kd (2 h2 Cos[[Theta]2] - b2 Sin[[Theta]2]) (b1 - (b1 + b2) ...
2
votes
1answer
54 views

contour plot using Mathematica

I want do a contour plot in Mathematica as: ContourPlot[{Re[F[5/4, x + I y]] == 0, Im[F[5/4, x + I y]] == 0}, {x, -20, 20}, {y, -20, 20}, PlotPoints -> 100]; where function F[b,z] is defined ...
0
votes
1answer
41 views

Help with Complicated Definite Integral

I am trying to find the integral of the following expression, with respect to $t$ from $0$ to infinity: $$\frac{e^{-a g t} \left(b-(g-1) \left(\text{H0} \left(e^{a t (-b+g- ...
1
vote
0answers
21 views

Is there any interactive spline fitting software?

I'd like to know if there's any software (freeware) for interactive data interpolation. What I want is to be able to visualize my data on an XY plot and drag the points to see how it affects the ...
0
votes
1answer
36 views

Mathematica Output Meaning ({{}}) [closed]

What does an output of {{}} mean in mathematica after solving a system? Best Regards
0
votes
1answer
29 views

Trying to calculate 5 simultanious equations in Mathematica

$\def\1{x_1}\def\2{x_2}\def\3{x_3}\def\f{f(\1,\2,\3)}\def\bs{\bigskip}\def\b{\begin{pmatrix}}\def\e{ ...
1
vote
1answer
57 views

Why is a complex number plus infinity equal to infinity?

Why is $$2 + 3 i + \infty = \infty$$ according to Mathematica and Wolfram Alpha? Shouldn't it be: $$2 + 3 i + \infty = \infty + 3 i$$ ? After all: $$2 + 3 i + 10 = 12 + 3 i$$ and not: $$2 + 3 i ...
1
vote
0answers
20 views

Computer Code Friendly Books On Differential Equations?

When I need a differential equation for this or that application I generally search (by hand) through old paper and ink books written by mechanical or electronical (electrical) engineers. Sometimes my ...
0
votes
0answers
78 views

SAGE vs. Mathematica for Lie algebras / groups?

What math software is better for working with Lie algebras and Lie groups, SAGE or Mathematica?
0
votes
0answers
48 views

Finding circle which touches two functions

I wasn't sure whether my issue is with my Mathematica code or the actual way I am trying to figure out my problem so if it is a Mathematica issue I can ask it on that stack exchange. Firstly I have ...
0
votes
0answers
34 views

traingular matrix

I am not much in to the matrices. so I am sorry if I can not put forward the question properly. Assume $G_{n\times n}$ is a rank $n$ matrix (Indeed $G$ is the generator matrix of a lattice). I need ...
2
votes
2answers
49 views

Help finding a summation using CAS

While approximating an integral by midpoint rule, I ended up with $$\iint_R f(x, y)\hspace{1mm}dA\approx \dfrac{1}{n^2}\sum_{i=0}^{n-1}\sum_{j=0}^{n-1} f\left[\dfrac{1}{2n}+\dfrac{i}{n},\hspace{3mm} ...
0
votes
0answers
25 views

Need Suggestion: good CAD tool to solve inequality

I want to solve the inequality: $f(x,y,z,w)-g(x,y,z,w)>0$ $s.t. $ $ x>0$, $0<y<1$, $ z>0$ , $ 0<=w<=1$, $f(x,y,z,w)>1,$ $g(x,y,z,w)>1$ where $f$ and ...
0
votes
0answers
55 views

Implementing formula correctly in matlab for neuroscience: total soma membrane potential?

Please help me to understand: am I correctly implementing a total soma membrane potential (TSMP) equation in Matlab? Due to being a new member I need to use this list link to refer to the links ...
1
vote
1answer
61 views

Solution to second order differential equation

I'm reading a paper in which the authors solve the following equation: $\frac{d^{2}}{dz^{2}}\hat{p}$($\bf{q}$$,z)$-$q^{2}\hat{p}$($\bf{q}$$,z)$-$\frac{iq_{y}}{(2\pi)^{2}}\delta(z-z_{2})$=0 here ...
-1
votes
1answer
35 views

poisitive definite matrix imply matrix of full rank? [closed]

Is a positive definite matrix always of full rank? while is given that the characteristic roots are pisitive
1
vote
1answer
35 views

Conversion of Hypergeometric functions from Maple to Mathematica

After a calculation I found in Maple an expression of the kind: $$f(x)=hypergeom\left(\left[\dfrac{a}{b},1\right],\left[c,d\right],h\right)$$ What is the equivalent notation in Mathematica which I ...
0
votes
0answers
40 views

Solving partial differential equation with mathematica.

I am trying to solve the heat equation in cylindrical coordinate. The object of inspection is a thick ring with height $\{z_0,z_L\}$ and radii $\{r_1,r_2\}$ within a heat generating environment. I ...