## 202 Reputation

4 years, 240 days

## What does it mean when DESol has an arbi...

Maple 2023

I have a thirder order ODE with non polynomial coefficients and I naively thought to try dsolve for fun to see what happens and Maple returned DESol with a second order differential equation and an arbitrary coefficient. I know Maple outputs DESol when it cannot find a solution similar to RootOf but the arbitrary constant is what is throwing me off.

I am unsure how to interpret this, if a particular solution is found I could reduce the order and see how I could get with the second order ODE but maple doesn't produce a particular solution when I run that command.

DESol_Question.mw

## Is this a bug or does Maple hate me? ...

Maple 2023

I am running Maple 2023 - yes I should update - and I found a weird "bug" if you could call it that. For different versions of the Physics package I am getting different answers on the same problem.

This is what I was getting when I run Version 1410:

 > restart;
 > with(Physics):

 > Physics:-Version()
 (1)
 > Setup(mathematicalnotation=true):
 > g_[arbitrary]:
 (2)
 > LG :=(g_[~mu,~nu]*Ricci[mu,nu])*sqrt(-%g_[determinant]);
 (3)
 > SG:=Intc(LG,X)
 (4)
 > EQ:=Fundiff(SG,%g_[~delta,~gamma])/sqrt(-%g_[determinant])
 (5)
 > Simplify(subs(%g_=g_,EQ))
 (6)
 >
 >

And this is what I get if I used the latet update for 2023, Version 1683:

 > restart;
 > with(Physics):
 > Physics:-Version();
 (1)
 > Setup(mathematicalnotation=true):
 > g_[arbitrary]:
 (2)
 > LG :=(g_[~mu,~nu]*Ricci[mu,nu])*sqrt(-%g_[determinant]);
 (3)
 > SG:=Intc(LG,X)
 (4)
 > EQ:=Fundiff(SG,%g_[~delta,~gamma])/sqrt(-%g_[determinant])
 (5)
 > Simplify(subs(%g_=g_,EQ))
 (6)
 >

Strange right? I bring this up because it makes me wonder about potential errors in other computations...

The answer - equation 6 - in 1410 is the correct answer. This is simply a derivation of the Einstein Tensor.

## Any ideas about why this numeric integra...

Maple 2023

I have a double for loop which has a numeric integration located inside of the innermost loop. When I try to run my worksheet I recieve an error in which the numeric integration is not computed for a certain set of values in my loops. If I take these two values and input them into my function and then integrate outside of the loop it appears to work just fine. Not sure what to make of this. Any thoughts would be appreciated.

Secondly, to avoid any confusion about what I am trying to do and if someone has general comments on my worksheet I added some text in the worksheet to describe what I am interested in doing, even though I am sure most people here would be able to figure that out from the commands alone.

Thanks.

LoopError.mw

## Can anyone help me with this Physics iss...

Maple 2023

I have a complicated tensor expression that is defined wtih all indices down. However if i consider a one-up-one-down configuration it appears to introduce new terms that no longer produce the same result as the all down configuration. Not sure what to make of this.

IndexQuestion.mw

## What is the policy on re-asking a questi...

MaplePrimes

I asked a question a while ago

https://www.mapleprimes.com/questions/235734-How-Can-The-Functional-Derivativevariation

Which did not get any immediate responses but one late one which i had replied to, but nothing else since then.

Is it appropriate to delete and repost and try to get more responses/exposure and see if anyone else has any ideas?

Since @ecterrab is the one who responded I consider this an interesting problem that I would like to continue discussing.

 1 2 3 4 5 Page 1 of 5
﻿