Questions tagged [convergence]
The convergence tag has no usage guidance.
28
questions
0
votes
1answer
71 views
Increase convergence near singular point
I have this integrand given by tinteg[z,zm,zh] where I want to integrate it in the range [0,zh]. However, the integrand is ...
2
votes
0answers
64 views
NSum complaining of being non-numerical
I am trying to evaluate the sum $\sum_{k,l=1}^{30}\frac{1}{(k^2+l^2+1)^{5/4}}$ so I write
NSum[1/(1 + k^2 + l^2)^(5/4), {k, 1, 30}, {l, 1, 30}]
but I get a message ...
2
votes
1answer
46 views
NDEigensystem convergence and comparison to DEigensystem
Consider the following eigenvalue differential equation
$$
-u_n''(x)+x^2u_n(x)=E_nu_n(x),\qquad x\in(-\infty,\infty).
$$
If you know a little bit of physics, you would know that this is the ...
0
votes
0answers
49 views
NDEigensystem eigenvalue convergence problem
I am solving an eigenvalue equation (a time independent schrödinger equation) and want to find the eigenvalues
...
0
votes
2answers
91 views
Calculating the convergence value of summation
Could you please tell me what value the left side of the inequality converges to?
(H and P are constant values greater than 2 and n can go to infinity)
$$\sum_{n=1}^...
0
votes
2answers
104 views
Convergence and efficiency of 5-dimensional numerical integral using “GlobalAdaptive”
We have a 5-dimensional integral arising as a solution to a physics problem, where two dimensions of the integration space cover the spherical and azimuthal angle, and three dimensions are needed to ...
5
votes
1answer
173 views
AceFEM: Divergence in iterative procedure (Newton-Raphson) for fine meshes
I am trying to model a problem of a nearly incompressible $10~\rm{m} \times 2~\rm{m}$ beam with a uniformly distributed end load. The beam has a Young's modulus of $200~\rm{Pa}$ and a Poisson's ratio ...
1
vote
1answer
52 views
How to do a convergence test on a complex series in Mathematica
I set the following to N=5, and want to do a convergence test on u:
...
6
votes
0answers
167 views
CORDIC - Volder's algorithm
As the title suggests, the object of this topic is the CORDIC algorithm (COordinate Rotation DIgital Computer). Although it's now obsolete in most cases, I think it can be interesting to understand ...
3
votes
2answers
97 views
Does this sum converge, and why?
Mathematica says the following sum
Sum[(mm Gamma[mm])/
Gamma[-(1/2) + mm] - (mm^(3/2) - (3 Sqrt[mm])/8 - (7 Sqrt[1/mm])/
128), {mm, 1, \[Infinity]}]
...
0
votes
1answer
78 views
Laplace Transform - Differentiation in Time property demonstration
I have a signal
x[t_]=t/3 Exp[-3t] UnitStep[t]
and the laplace transform as
...
0
votes
2answers
36 views
How to eliminate error: Numerical integration converging too slowly
While doing numerical integration, I am getting a result with the following error messages:
...
6
votes
2answers
124 views
Convergence Rate of NDSolve by Increasing the Spatial Grids
I have a very simple PDE equation, with an analytical solution (exact solution). And I want to play with NDSolve and increasing the number of Spatial Grids.
Here is the exact solution:(Analytical ...
1
vote
1answer
96 views
How can I determine the convergence rate of recurrence methods?
I want to solve the equation $x^{3}-x-1=0$ by iterating recurrence equations.
I have two different recurrence relations for solving this equation:
$x_{k+1}=\sqrt[3]{x_{k}+1} \quad(k=0,1, \cdots)$
$...
asked Oct 1 '20 at 2:20
A little mouse on the pampas
5,2002 gold badges10 silver badges28 bronze badges
2
votes
2answers
172 views
How to judge whether the series is absolutely convergent?
I need to judge whether the series $\sum_{n=1}^{\infty}(-1)^{n}\left(1-\cos \frac{\alpha}{n}\right)$ (α>0) is absolutely convergent.
...
asked Sep 1 '20 at 3:15
A little mouse on the pampas
5,2002 gold badges10 silver badges28 bronze badges
0
votes
1answer
77 views
Why is the function `SumConvergence` not valid for simple power series
I want to find the convergence interval of function $\sum_{n=1}^{\infty} \frac{1}{3^{n}+(-2)^{n}} \frac{x^{n}}{n}$.
...
asked Aug 22 '20 at 1:43
A little mouse on the pampas
5,2002 gold badges10 silver badges28 bronze badges
1
vote
1answer
305 views
How to get the convergence radius of the result of Series? [duplicate]
The Taylor expansion of function is very useful, but the convergence radius of power series results after Taylor expansion is also important. But the result of ...
asked Aug 12 '20 at 4:04
A little mouse on the pampas
5,2002 gold badges10 silver badges28 bronze badges
0
votes
1answer
97 views
How to verify whether the abnormal integral is convergent or divergent?
How to verify the convergence and divergence of the abnormal integrals $\int_{0}^{1} \frac{\sqrt[m]{\ln ^{2}(1-x)}}{\sqrt[n]{x}} d x$:
...
asked Aug 12 '20 at 1:29
A little mouse on the pampas
5,2002 gold badges10 silver badges28 bronze badges
6
votes
1answer
248 views
Improving mesh and NDSolve solution convergence
I have developed the code below to solve two PDEs; first mu[x,y] is solved for, then the results of mu are used to solve for phi[x,y]. The code works and converges on a solution as is, however, I ...
1
vote
1answer
55 views
Speeding up simultaneous numerical integration where some integrals vanish
I would like to carry out a number of numerical integrals in the form of a table:
...
0
votes
0answers
89 views
Plotting a complex integral function [duplicate]
Can anybody help me to plot the T1 and T2, please?
The problem is that the integral part becomes so huge or indeterminate at ...
3
votes
2answers
283 views
Code that produces plot in V5 doesn't work in later versions
I have problem in plotting Integral function.
I can compute/plot the graph of this integration below in Mathematica 5.0, but it is not possible to plot it in higher Mathematica versions.
My code is:
<...
1
vote
0answers
79 views
Why doesn't Mathematica provide an answer while Wolfram|Alpha does, concerning a series convergence?
Among other series I've been working on, I was asked to find whether
$$\sum_n 1-\cos(\frac{\pi}{n})$$
converged, and Mathematica's output to ...
0
votes
0answers
41 views
Nintegrate providing results much smaller than what is expected
This is the first time I am posting something here. So, apologies if I make any mistake. I am dealing with a numerical integration in Mathematica-11.0 that has a Bessel function in it. In order to ...
5
votes
2answers
767 views
Bug in Integrate?
In v. 11.1.0.0 Mathematica for Linux
Integrate[Sin[Cosh[t]], {t, 0, Infinity}]
returns
Integrate::idiv: Integral of Sin[Cosh[t]] does not converge on {0,[...
5
votes
1answer
248 views
Wolfram Language 12 says this absolutely convergent series does not converge. Is there any similar example?
I am reading "Lectures on complex function theory" by Takaaki Nomura.
In this book, there is the following example:
$\sum_{n=1}^{\infty} \sin(\pi(2+\sqrt{3})^n)$ converges absolutely.
But ...
6
votes
1answer
402 views
Strange result for sum $\sum _{k=1}^{\infty } \frac{\sin (k (k-1))}{k}$
In this sum over $k$
Sum[Sin[k (k - 1)]/k, {k, 1, ∞}]
the result still containes the summation index $k$.
...
1
vote
1answer
421 views
Repeated convergence test failure and why?
i have assigned all the values and the ODE assigned is as this
...
