Ralph White

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17 years, 357 days

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These are answers submitted by Ralph White


I'm new to Maple and to Maple - word on Internet, but I'm pleased I had join since many disccusion are of grat interest, and the athmosphere decisely serious which doesn't radiate sense of humor or hirony.

How these apparet oppositsView 7995_McConnell.mw on MapleNet or Download 7995_McConnell.mw
View file details

It is a work alla based on Matrix creation and manipulation, in order to solve a ODE system relating to NMR. What matters is the way the autor master the matrices. II followed step by step each indication on Maple 11 just to check if the mw was compatible with this maple edition and it is. You surely will take more advantages thanks to the fact that you already have esxperience worling on matrix... It is a great piece of work, and commented too, all along.

Hope can be usefull.

Take care




Perapohs your post concern at not easy problem, and peoples, as I did myself pass look and turns away not knowing how yo help you. This is can be the case... .

For instace looking up at the content of your post, I see something interesting but I do not understand a thing ... I never worked with arrays, matrices and so on...

Perhaps you might ask someone you know has got the skills for it to give you an help, using a personal message or so.

So, do not be disappointed, it can just be a "logistic and (negative) conjuntural problem" (to be study with time series and cues-theories ehehe :-) .

Futhermore, why asking for help in a place where evrerybody do the same,  in your case  would "stumped" anyone?

I hope and think somehone would show up ...

Take care





here the Maple bit I manage to go through hope it'll be of some

View 7995_A possible solution to a laplace transf problem 25 4 2008.mw on MapleNet or Download 7995_A possible solution to a laplace transf problem 25 4 2008.mw
View file details

EUREKA! is my first positive link insertion!



with a stamp it's all properly done




The contest: http://www.mapleprimes.com/files/221_laplace_method.mws

The propose solution: http://www.mapleprimes.com/forum/howinsertinitialconditionslaplace

The ditails: http://www.mapleprimes.com/viewfile/2494

The youl find the reference to write directly to him in the 'contestusl' page


be good



I know there is a magician for laplace trnsofm here on the Maple primes site, unfortunately for you that's no me.

Though I gave a go to your problem

There is no way to get the transfom stright away with the formula containinig the argument sin(W*t)

so I did the transform of the following funcrion just using the command from the menu of Maple 11.

  y = (1-eSqr(x)) / (1-Sqr(x))

which transform is really nice:  

Sqr(Pi/s)*(1-e(1/4*s) * erfc(-1/(2*Sqr(s))

The result is ok: the invlaplace returns the original function.

Peraphs you'll say so what?

I answer (to my self) perphs it knows the way of relating s with sin(W*t), i. e. some rules about laplace transorms or some proprieties of this transormation that I ingnore wether for you the way home about getting your transofmation will be clear and easy.

Just hopes?

Hope not



PS ... do not worry the Laplace tranform Magician will come to hel you, and there was a trig problem there as well. Time to find the links & I'll be back to you, with the links of course.




I'm new to Maple and to Maple - word on Internet, but I'm pleased I had join since many disccusion are of grat interest, and the athmosphere decisely serious which doesn't radiate sense of humor or hirony.

How these apparet opposits

I beg your pardon sir, but certain language....

I just try to help up to my abilities

"twhat" yourself sir



Can not upload the Editor, not even after having change is name in Lucy, the extension in txt and zip all up ... sig & ;-)

here the direct link http://www.editpadpro.com/cgi-bin/SetupEditPadProDemo.exe

hope not against the local (CIA).




I have saved the TEXT file you posted as *.java file using  editor EDIT PAD PRO, I chose to open the java file with Maple 11, and your hard work column were there nicely red & sound.

I load the file on my account, just in case the link here wouldn't work

<a href='http://mapleoracles.maplesoft.com:8080/maplenet/primes/worksheet/7995_The data_java_Maple Input.mw'>View 7995_The data_java_Maple Input.mw on MapleNet</a> or <a href='http://www.mapleprimes.com/files/7995_The data_java_Maple Input.mw'>Download 7995_The data_java_Maple Input.mw</a><br/><a href='http://www.mapleprimes.com/viewfile/2509'>View file details</a>

as usual!!!! no direct link $%£%$£$%£%&£%£%£%$£$%£%£%$/$/59786780978'

I have been polite eheh

Just go to my files and try gettin it

if it doesn't work if you agree I'll sendit by e-mail, as already appened amongst us.

PS The editor sould be there too for when you get the file

Take care



Ciao, I try using factor simply selecting your expression, and things came in order first Q then S.

I do know if the command alterate the original formula, since I'm not a Maple expert.

I'm not sure either this will answer your question since you are talking about operators (that I assumed be Qand S, but as  said I might be wrong)

Nevetheless it's worted to at list propose it...

take care




set to print the Maple page, but choose the virtual postscrip printer that Acrobat  install by default, chose "print to file" as psot-scrip file (ps), rescue that file and ask Acrobat to convert the ps file to PDF, ... it takes more to say it than do it.

NB remember to select the folder were to save the ps file, othervise you'll find it within Acrobat installation folder.

Hope it works for you as well



He's me again just to give you trhe title of a Mastepiece on PDE

Hans WEINBERG, A fisrt course in Partial Differential Equation,

Univ. Minnesota 1965.

i.e the first chapter "A one dimensional vawe equation" lasts for 40 dense pages!

The second chapter , "Linear second order Partial Differential Equations, in two variables" spans 18 pages and gives as referencies for further readings: 1) R.V Churchill, Fourier Series and Boundary Value Proplems, 1963 CH X, 2) R. Courant and D. Hilbert, Methods of Mathematical Physics, Vol 2, 1962, CH III, 3) I.G.Petrowsky, Lectures on P.D.E, 1954, CH I, 4) H. Sagan, Boundary and Eigenvalkue Problem in Mathematical Physics, 1962, CH II.

I do have the Weiberg Book in DJV format but is 3.09 MB, too big to be uploaded on Maple site. I'll try to get at least the first chapter out... see as it will go, then if I'll succed it will be among my files

In the meanwhile, e-mule can be usefull for good thing once, since this papers are avaliable on P2P. Or, by sure in your College Library.

Take care




the substitution I made at the end by f(x,y) was just to get the point, you are asking for: how to solve such a "monster"? I followed once the rid of assumption one has to make starting with the contour conditions, and further down at each step of the solution process. The autor called the art of approximation: the sense to me, was that not alla information stored in a PDE can be explicitated analitically. At the end of that classics for PDE solving, the moral was a lot of experience, good nose,m and a great patience + good guess skiils to approximate the real solution, asking the solving function to be the list linear, smooth, computable, regular, and so on. And alla this was just about solving the vawe equation a second degree PDE! I do not hgave a clou about getting somthing out a Fifit degree PDE... assuming I would'n know the original function. But since we know is cos(x*y), in place of f(x,y) I woul put g(x*y) aiming not to the specific cos(x*y) but a more generical function, having though something in common with the original one. This I feel to be the exiciting bit out of a predetermined PDE (we knows already the answer). But since starting at the 4th derivative gerality comes in, the final PDE, musty account for a general kind of solution, and not just cos(x*y). How to find it, I sad it, f(x,y)=g(x*y) differetiate, put back in the final formula plus assuming D''(g(x+y)=-g(x*y), i.e. making some hypotesis about the parity and the simmetry of the candidate function.

But I'm not a mathematician ... so ... I must admit one thing is to evisage the scenazio, an other thing is to know how to move correctly among its maths objects.

Take care and have a nice journy at PDE land.



I guess the meaning of making this calculation is to get a grasp on the effect os order partial derivation on your periodical function.So is a fifth order PDiff, order 3 in y and 2 in x of cos(x*Y).

I guess you have 6 ways to get to the PDiff requested.

The question might be: "which one I choose?"

"I first derive twice for x then three times for y, or the opposite?"

Or, " I alternate the derivation firs by y, then by x, ... by y ...?"

Just write the formula for your equation. Personally, in order to haveexplicitly the order of derivation on the left side I do not define theequation, but I equate f(x,y)=cos(x*y). Then I ask Maple to do the job,I simply select the equation and choose differentiate for x then for yor viceversa up to the fifth degree twice by x and three times by y. Idid ite for the different possible combination in precedence of x and y.

The result is that no matter the derivation pattern already at thefourth differentiation cicle the result is the same for all thecombination in sequence.

Peraphs is this the purpose of you theacher, making you aware of howdifferentiation looses memory of the specificity of differential orderafter the thirt l cicle (3°) in the particular case od cos(x,y).

By substituting the general f(x,y) partial derivatives, in place ofsin(x*y) and cos(x*y) you'll obtain a fourth or fifth degree PDE, whichdoesn't know anymore from were it cames from... A triky bit going backto cos(x*y) from there, assuming yourself had an amnesia .. eheh. Plus in doing this substitution you'll have 2 different possibilities having to use the prime partial derivatives.

I wish I could put a formula here, but though I'd followed the instructions, just a x appeared. Equ1 and Equ2, the fifth order Pdiff and one PDE by substitution are among my files oon the Maple account, hope you could see them from there. Nevetheless you find enclosed the two HTLM in the PS

I might be wrong, I'm not a mathematician, this is all I can think theexercise mean to do. Check it with other friends on Maple Primes, your teacher himself.



<a href='http://www.mapleprimes.com/viewfile/2490'><img src='http://www.mapleprimes.com/scripts/image.php?image=http://www.mapleprimes.com/files/7995_Eqn1.gif&width=300&height=300'/></a></a>


<a href='http://www.mapleprimes.com/viewfile/2491'><img src='http://www.mapleprimes.com/scripts/image.php?image=http://www.mapleprimes.com/files/7995_Eqn2.gif&width=300&height=300'/></a></a>

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