In preparation for learning GR, I need somme trick on how to use the DifferentialGEometry package or else. So I want to show you what I want to do (see the link to the document below) and I would like some help on how to do it with tensor.  That would help me a lot.  Then, I will extansion it on a 3-D problem and next in 4-D.

Thank you in advance dor your help

here is the file : Finding_covariant_and_contravariant.mw

--------------------------------------
Mario Lemelin

Maple 2015 Ubuntu 14.04 - 64 bits
Maple 2015 Win 10 -  64 bits
messagerie : mario.lemelin@cgocable.ca
téléphone :  (819) 376-0987

Hello to you all,

I have this DE

but when I try to change the variable

I get this

>algsubs(r(t) = 1/u(t), diff(diff(r(t), t), t)-k/r(t) = -K/r(t)^2);

Why is it not done for the rest of the terms.  Is there a more easy way to do it.  Take into account that I cannot use dsolve because it is in an course in integral.

Thank in advance for your help.

--------------------------------------
Mario Lemelin

Maple 2015 Ubuntu 14.04 - 64 bits
Maple 2015 Win 10 Pro -  64 bits
messagerie : mario.lemelin@cgocable.ca
téléphone :  (819) 376-0987

Hello,

In a course I am looking at, the system of units is mostly in FPS.  Wich I never use.  But they ask sometime to convert it to SI.  But with Maple, I have a problem:

For Force, it use lb that I cannot convert into N

So what unit should I use to convert FPS to SI for the force.

I know that slug*ft*s^(-2) convert to N with no problem.

Thank you for your help.

--------------------------------------
Mario Lemelin

Maple 2015 Ubuntu 14.04 - 64 bits
Maple 2015 Win 7 -  64 bits
messagerie : mario.lemelin@cgocable.ca
téléphone :  (819) 376-0987

Hi,

I want to compute the determinant of a matrix A with this formula:

 Can someone help me to do it.  Of course, here I am using Einstein's convention.

Thank you in advance.

--------------------------------------
Mario Lemelin

Maple 18 Ubuntu 14.04 LTS - 64 bits
Maple 18 Win 7 Pro -  64 bits
messagerie : mario.lemelin@cgocable.ca
téléphone :  (819) 376-0987

Hello everybody,

I will start a course in mastering QM in a MOOC format (Massive Open Online Course).  Up to now, I always do the calculation by hand and sometimes with the LinearAlgebra package.  But now I need to do the calculation more rapidly.  So I decided to learn how to use this package for this course.

The help system give a too generalized way to do it.  Even by looking the example, I didn't find praticle example to it.  So is there a generous person who could take a little bit of hi time to show me how to do it by using an exemple that yo will find attach to this post.

Thank you in advance for your trouble.

Besgt regards.

quantum_mechanics_DIRAC.mw

--------------------------------------
Mario Lemelin

Maple 18.2 Win 7 and Ubuntu 14.04 - 64 bits
MapleSim 7 Win 7 and Ubuntu 14.04 - 64 bits
messagerie : mario.lemelin@cgocable.ca
téléphone :  (819) 376-0987