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1answer
32 views

Mathematica Output Meaning ({{}}) [on hold]

What does an output of {{}} mean in mathematica after solving a system? Best Regards
0
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1answer
28 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
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1answer
40 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
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0answers
14 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 ...
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0answers
30 views

SAGE vs. Mathematica for Lie algebras / groups?

What math software is better for working with Lie algebras and Lie groups, SAGE or Mathematica?
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0answers
42 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
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0answers
31 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
43 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
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0answers
21 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
23 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
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1answer
44 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
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1answer
28 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
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1answer
22 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
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0answers
34 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 ...
0
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0answers
37 views

complex ordinary differential equation of a real variable

reading a paper i have found the following differential equation: f''[z] - (q^2)*f[z] == i*DiracDelta[z] here f[z] is a complex function of the real variable z ...
0
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0answers
26 views

How to interpolate and obtain this graph?

I was interpolating with software mathematica v9, but how can I obtain a curve similar to this?, in a easy way
3
votes
4answers
77 views

indefinite integral computation $dx/(e^{-x}-x)$

Hi i'm trying to carry out the following indefinite integral: $$\int \frac{1}{e^{-q} - q} \, dq$$ mathematica is not helping me, and i think it is not solvable by substitution method. any idea on ...
0
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0answers
25 views

Splitting a list into two lists, depending on a condition.

So I have this list of n real numbers called A, which is sorted least to greatest. Let B be a list of n real numbers with NormalDistribution[]. IF A+B = Sort[A+B], then we keep it, and if A+B != ...
0
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0answers
59 views

Mathematica Integrate gives back the integrand

i'm trying to Integrate the following function: (q (1 + q) - E^-q Sinh[q])/(-q + Cosh[q] Sinh[q]) - ( 2 q Tanh[q])/(-q + Cosh[q] Sinh[q]) I already solved ...
1
vote
1answer
26 views

Reduced Residue System in Mathematica

How can I create the standard reduced residue system modulo $m$ in Mathematica for a given positive integer $m$? For example, if I input $10$, I would like it to give me the list $\{1,3,7,9\}$. ...
2
votes
1answer
46 views

Fourier series of oscillation in form $\cos(2 \pi \frac{k}{T}+\phi)$

I would like to calculate the fourier coefficients of $\cos(2 \pi \frac{k}{T}+\phi)$ where $T \in \mathbb{N}$ is the period and is arbitrary but fixed, $k \in [1, N-1]$ is the number of oscillations ...
3
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7answers
198 views

Best Math Plotting Software for Electrical Engineering

I am an electrical engineering undergrad. I would like to learn a math plotting software which would be helpful in visualizing topics in advanced calculus (my immediate need). It would also be helpful ...
1
vote
0answers
17 views

Can nodes of Gaussian quadrature shift range?

I used my Python program to generate Gaussian's nodes and their weights. My python program could generate nodes as default in rage of (-1, 1). And my friend used Mathematica to generate them also but ...
0
votes
1answer
18 views

Filling between two curves in Mathematica [closed]

I want to fill region between 2 curves, but in mathematica 8.0 FilledListPlot[list1, list2, Fills -> {RGBColor[f, f, f]}] doesn't work. can someone help me? Thx
6
votes
1answer
153 views

Odd Mathematica series result

I asked Mathematica to evaluate $$\sum_{i=1}^{\infty} \cos(i a)\cos(i b)$$ where $a$ and $b$ are unspecified real numbers, and it told me the answer was simply $-\frac{1}{2}$. This is clearly wrong, ...
2
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0answers
21 views

Algorithm for FindSequenceFunction

What algorithm might Mathematica be using to compute FindSequenceFunction? Does anybody know if there is any online material on this topic?
3
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4answers
153 views

A limit question (JEE $2014$)

The following is a JEE (A national level entrance test) question: Find the largest value of the non-negative integer ( a ) for which: $$ \displaystyle \lim_{x \to 1} \left( \dfrac{-ax + \sin(x-1) + ...
0
votes
0answers
33 views

list of all irreducible polynomials of degree at most n over the field Z/PZ.

I am trying to write a mathematica coding to give me the list of all irreducible polynomials of degree at most n over the field Z/PZ. I started by defining univariate polynomials of the form p = a_0 + ...
1
vote
0answers
21 views

Two factor ANOVA discrepancy with Mathematica

I have a set of two factor data I am doing ANOVA analysis on, both with Mathematica's package and manually (because learning!) Using one set of example data (found here 1) both my manual calculation ...
0
votes
2answers
182 views

Is this computation erroneous?

The solution to $\lim_{n\to\infty}\frac{n^{100}}{2^{n/100}}$ should be $\infty$ because $n^{100}$ grows much faster than $2^{n/100}$ But if you input ...
4
votes
1answer
58 views

Finding the period of the solution to $y'(x) = y(x) \cdot cos(x + y(x))$ with Fourier transform; how to interpret complex result?

A question elsewhere on this site asks about detecting the frequency of oscillations in a system defined by differential equations. The equation is $y'(x) = y(x) \cdot cos(x + y(x))$. The solution ...
1
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0answers
33 views

How to evaluate Bessel functions $K_{i x+\frac{9}{4}}(2\pi)+K_{i x-\frac{9}{4}}(2\pi)$ with $x>1.5*10^8$ in Mathematica 7?

I am trying to evaluate Bessel functions $K_{i x+\frac{9}{4}}(2\pi)+K_{i x-\frac{9}{4}}(2\pi)$ with $x>1.5*10^8$ in Mathematica 7. This function is the first Polya approximation to Riemann ...
0
votes
1answer
69 views

Partition a set into n subsets with elements with sum equal to m

For example, given the set $a_n = \frac{n}{20}$ for $\,n \in \{1,\,2,\,\dots,\,19\}$, I would like to get all possible partitions of this set in 4 subsets such that the sum of their elements is always ...
1
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0answers
39 views

Plotting in Mathematica

I'm new to mathematica. How would I plot the following functions in the polar complex plane? $$ \phi={-k\over 2\pi r}\cos(\theta_0-\theta) $$ and $$ \psi={-k\over 2\pi r}\sin(\theta_0-\theta) $$ ...
0
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0answers
52 views

In Maple or Mathematica, syntax : Finding the fundamental sol. of the Heat eq., with Dirac-Delta initial condition

I use this question as a case example for later solving more complex equations of this type : When trying to find the fundamental solution of the Heat equation using Maple (software) , I get the ...
1
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0answers
78 views

What is the Fourier series of $e^{\mu\cos\theta}$?

Motivation: I want to solve this convolution problem on the circle: find $f$, given $g$ and $$ g(\theta) = \int_{S^1} e^{\mu\cos(\theta-\phi)}g(\phi)\ d\phi. $$ To do this, I want to find the Fourier ...
0
votes
3answers
65 views

Plotting a region in $3D$ space

I would like to know if someone knows of a software where I can plot the following region $$ D = \{ (x,y,z) \in \mathbb{R}^3: 0 \leq x \leq 1 , \; x^2 \leq y \leq x, \; \; 0 \leq z \leq x \} $$ ...
1
vote
0answers
29 views

Roots and Weights

I use a Mathematica package to compute roots and weights (and other things) but the package gives me only the expression of the roots in $\omega$-basis (basis of fundamental weights) and in the ...
2
votes
1answer
38 views

How does the base of a group determine the “sort” of the elements in the group

I'm trying to study groups in Mathematica, and I've asked a question on Mathematica.SE that perhaps only someone from Math.SE could answer. Related: How does ...
5
votes
3answers
114 views

Find min of $\frac{\left( \sum kx_k \right) \left( \sum x^2_k \right)}{\left( \sum x_k \right)^3}$

With $n \ge 2$ and $x_1,\ x_2,\ \dots,\ x_n > 0$. Find the minimum of: $$ M = \frac{(x_1 + 2 x_2 + ...+ nx_n)( x^2_1 + x^2_2 +...+x^2_n)} {\left( x_1 + x_2 +...+ x_n \right)^3}$$ For specific ...
1
vote
0answers
67 views

Which symbolic programming language for manipulation of nonlinear equations?

I have a set of (multivariate, nonlinear) equations which I want wo modify according to my own rules, i.e. not in a standard ways such as matlab's simplify function. I am looking for a mathematical ...
1
vote
1answer
27 views

Mathematica DSolve input

I'm trying to solve this differetial eqation. dy/dx=3y^(2/3). This is my input: DSolve[{y'[x] = 3 y[x]^(2/3), y[2] = 0}, y[x], x] This is my output: DSolve::deqn: "Equation or list of equations ...
0
votes
2answers
58 views

Difficulty finding Expectation of a special function

I have a special function given as: $${\rm f}\left(r\right) ={1 \over \beta\lambda}\,2^{r/\beta} \exp\left({\left[2^{r/\beta} - 1\right]K \over \lambda}\right)$$ I should find the Expectation of ...
0
votes
1answer
45 views

Mathematica Homework Question

I had a mathematica assignment the other day that was fairly simple. I thought I did it correctly, but I guess not. Question: Write a single Mathematica Command which will display (plot) both $y = ...
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votes
0answers
15 views

Mathematica question about value of a function

I wrote this on Mathematica. *f[x_] := Prime[x + 1] - 1 g[x_] := (6 - (f[x]*f[x]) - f[x])/(2*log[f[x]]) + 2* ExpIntegralEi[2*log[f[x]]] + LogIntegral[f[x]] - (2*x*x) - (2*x) N[g[1200]]* I pressed ...
0
votes
0answers
25 views

Condition number of covariance matrix

I am interested in generating a covariance matrix of dimension say 100. I managed to get a correlation matrix with finite condition number. To construct a covariance matrix I need to have standard ...
1
vote
1answer
91 views

Good software package to help Maths learning

I'm a mature student enrolling at a Maths degree course soon at the university. I'd like to be able to use some software package to help me visualize equations, graphs, play around with variables with ...
0
votes
1answer
55 views

How to Expand $f(x) = \sqrt{x^2-y^2}$ about $x=y$

How would one go about expanding $f(x) = \sqrt{x^2-y^2}$ about $x=y$? You can't do a Taylor series, because $f'(x=y)$ diverges. I tried a few other things, but to no avail. Interestingly enough, ...
2
votes
1answer
95 views

Can wolfram alpha compute symbolic vector derivatives

Can Wolfram alpha be used to find out say $$\nabla_x\left(\|y-Ax\|_2\right)$$ What command do I use? I tried some obvious ways, and googled a bit, but didn't find anything.
0
votes
1answer
28 views

fourier transforms with Woflram Alpha

I'm studying Fourier transform at the moment and I've noticed some weird irregularities between my textbook and Wolfram Alpha's answers. Say I ask Wolfram the following: fourier transform ...