## 125 Reputation

15 years, 288 days

## You are correct...

@vv I realized that after playing around with the command. However, using 'a' may help the student step through the process.  Thanks.

## Perfect!!...

@mmcdara Fantastic!! TY TY TY

My students won't be happy with you, but I support you! :-))

## No...

In physics one needs to factor based on conditions:

L >> z

L/(z*L*sqrt((z/L)^2 + 1) -> 1/z

z >> L

L/(z*z*sqrt(1+(L/z)^2) -> L/z^2

I just need the commands in Maple that accomplish the same thing

## factoring again...

L/(z*sqrt(z^2 + L^2)

In physics one needs to factor based on conditions:

L >> z

L/(z*L*sqrt((z/L)^2 + 1) -> 1/z

z >> L

L/(z*z*sqrt(1+(L/z)^2) -> L/z^2

I just need the commands in Maple that accomplish the same thing

## Thanks...

I tried subs and algsubs but they were not working.  I installed the latest Physics module and now subs seems to work. However, convert does not work for direct %d_ to D. I did not want to convert %d_ to d_ because I am trying to write the differentials in terms of the directional tetrad derivatives, so I just want to represent the general differential forms.

Thank you. I should be okay for now.

Michael

## You are correct...

Thanks! I was not thinking. I changed the loop for p and q and it works.

Michael

## Correction...

Your reply confirmed my result. Using Maple, i solved each term individually, I then saw where the coefficients cancelled. Sorry, I missed it when I did it by hand. Must have missed a negative.  Thanks.

Michael

## Maple is great!!...

There is NO error with Maple! I figured out that the paper dropped the second term because they are equal to zero.

\Gamma_{423} = Y_{,3} + H Y_{,4}, however \Gamma_{424}=Y_{,4}=0. The second term in \Gamma_{423} is zero so the author decided not to print it.

## You are correct...

Edgardo,

Thank you. I appreciate your help, but I have a problem. Maple and I agree on the caluculations. Debney (1973) calculated different rotation coefficients for 423, 413, 341 and 342.  I would appreciate any help on pointing me in the right direction to resolve this issue. I have inserted the table from the paper. I used Maple to check my calculations and found the previous discrepencies. The only way to get the same answer for 423 is to not use the Christoffel, but that is completely incorrect.

## Okay it works...

Thanks. I was confused because of the link.  The link provides the Physics_DE_MathFunction as a single file. Maple had separate zip files before.  Anyway, you were correct it works.  Thanks for the help.

Michael

## Yeah my thoughts exactly...

Yeah I thought about that. That problem occurred with Maple 18. When the new update arrived I went to the reasearch and development page but the link for physics Maple 2015 takes me to the Special Functions link. I assumed that there were no updates yet for Maple 2015 but I will try again.

Michael

## I think the labels are the problem not a...

Okay, I think that I found the problem. I directly cut and paste the lines (9) and (19) into the algsubs command. Maple 2015 gives the correct result.  When I put the labels into the command I get 0=0. For some reason the command is not interpreting the line labels. If I define the output with a variable, then algsubs works.

Line 20: The direct cut and paste of the equations

Line 21: Using output labels

Line 22: Using variables for the equations

Michael

Question_algsubs_3.27.15_(modified).mw

## Simplification info...

Sorry about the mixup on the pasted image, I thought that I was pasting the commands from the worksheet.

Your reviewed copy is exactly my point.  The result you get is what I get using Maple 18.  The result I show (0=0) is the result I get using Maple 2015.  The same file gives different results. The Maple 18 result is the correct result. I have tried uninstalling and reinstalling Maple 2015 and Maple 18, but the result is the same.

I am using Maple 2015.0 for the Macintosh. Could the Macintosh version be doing something wierd. I am running on Mac OSX 10.10.2

I am at a loss. My guess is something happened durinhg the installation. Everything else seems to be loaded and working with Maple 2015.

Michael

## Simplification info...

Okay, the equation

Should have the substitution

Which should make it

## Thanks....

you folks are always great. I appreciate the help.

michael

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