Maple Questions and Posts

These are Posts and Questions associated with the product, Maple


diff(u(x,t),t,t)=c^2*diff(u(x,t),x,x);
 Where u(x,0)=f(x),D[2](u)(x,0)=g(x),u(0,t)=0=u(0,1)

 



Maple_for_Beginners.mw

Edgardo S. Cheb-Terrab
Physics, Differential Equations and Mathematical Functions, Maplesoft

I keep getting errors empty sets or only header information using the HTTP or URL package to when trying to download files from here through Maple. 

How do I download the csv files from here?
https://github.com/CSSEGISandData/COVID-19/tree/master/csse_covid_19_data/csse_covid_19_time_series

 

Hello,

is it possible to solve the attached partial differential equation with zero initial boundary condition?

If not by assuming diff(u(sigma, tau, phi, t), t, t)=0 is there an answer for the equation?

Thanks

lapla.mw

Is there anyway to animate d'Alemberts wave solution as time goes on? 

Suppose I have the initial value problem:

PDE:   utt = uxx

ICS:    u(x,0) = x

            ut(x,0) = f(x)

where f(x) is piecewise defined as:

f(x) = cos(pi*x), -1/2 < x < 1/2               and

             0             otherwise

Hello, I was wondering about the following.

cos(Pi/2^n) can be converted to a radical for each integer n, because cos(Pi/2)=0 is known and successively

cos(x)=sqrt( (1+cos(2x))/2 )

so in principle radical expressions should exist for all integers n. But maple only converts cos(Pi/8) to a radical, but not cos(Pi/16) and higher powers. Is there a simple way without writing an own program to obtain these radical expressions using convert(*,radical)?

Suppose two following Eqs.:

(1) du/dt+d(u*w)/dx=0

(2) dw/dt+wdw/dx=0

I want to expand u(x,t) and w(x,t) in the power series of epsilon

u=u0+epsilon*u1+epsilon^2*u2+…

w=w0+epsilon*w1+epsilon^2*w2+…

and change the variables x,t to X,T as follows

 X=(x-alpha*t) and T=beta*t,

and solving Eqs. (1) and (2) for different order of epsilon (epsilon, epsilon^2, epsilon^3,…) to finding u0,w0,u1,w1,…

How do I do that?

Thanks.

 

Hello

Im trying to solve an energy functional with two independant variables. so the result would be a system of PDEs.

Ive checked

DEtools-Hamilton eq

and

vector calculus-EulerLagrange(f, t, x(t))

But I couldnt figure out how to use 2 independant variables in these commands.

 

Your help would be much appreciated

 

 

Does there exist a way in Maple that you can detect a change in a text file without having
to constantly having to call the readdata which keep the command prompt busy in Maple.

Maple 2018  has recently has  become sluggish to start up  -and very slow to respond to input. Can anyone suggest remedies?  I have plenty of space and CPU. Other apps seem to start fine.  Can any suggest a diagnosis and/or solution?

Melvin

How do I know that what numerical method has maple used in this code.?

dsolve({eq11,eq21,eq3,eq4,bc21,bc22},numeric,continuation=lambda1,maxmesh=15000, output=array([seq( i, i=0..N,0.01 )]))

Good day.

Reading through the Fuzzy C-Means routine (attached) written by the one-and-only Carl Love, I was wondering if anybody can tell me how to specify which points in the data belong most strongly to the assigned cluster. 

In the attached routine, there are 2 cases considered; two and three clusters. 

It would be interesting to obtain a list of all points that are assigned to each respective cluster.

Thanks for reading!

Fuzzy_clusters.mw

I have question how start histogram from 0? I have vector with probablity which start from 0.

I generate samples from my probablity:

pr=values of probablity

X:=RandomVariable(ProbablityTable(pr)):

A=Sample(X,1000):

Q=Histogram(A, binwidth=1,range=0..10):

...

I try to use bindwidth=-1 but it's impossible. 

How start histogram from 0 for vectors in maple15?

 
Hi !
 
I have been working for a long time to evaluate several infinites summations .
I often use a command like  "simplify(combine(sum1-sum2))"  to check if both summations are equal .
Now ,I found that the "simplify" command is not reliable at all . Check my file "simplify.mw" .
 
I have Maple 2017 and 2018 on Windows 10 .
I'm angry because I have to double check all of my work trying not to use this buggy command.
If someone can confirm that the 2020 version of Maple has an improved "simplify" command , I will buy it immediately.
 
Thank you !
Rejean

Hello I am trying to compute the following expression;

 

(x^2r+y^2+z^2) gamma^{0} partial_{x} (-xy(1-r)) gamma^{2} partial_{y} \Psi

 

in which r = sqrt(1-K(x^2+y^2+z^2)), K is a constant, the gamma's are the Dirac gamma matrices and \Psi is the wave function. Essentially I would like to have partial_{x} operate on the expression to the right of it and apply product rule where there will be three terms with the last one being partia_{x} partial_{y} \Psi where it evaluates on everything expect the partial and the wavefunction, combining into the term partial_{x} partial_{y} \Psi, and if the partials are the same they combine into a single second order derivative with respect to the given variable. I have done this calculation by hand but seeing that there is an extensive amount of terms I would like to automate it using Maple. I have tried using the D() calling sequence but it doesn't quite give me what I am looking for. Is there anything documentation which will give me what I am looking for?

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