Oliveira

I  am attaching a Maple document for better understanding.Test_with_uses.mw

Yes it is true, but in the above procedure (gds) with the Physics package, the package commands are not confined to proc, they leak acting on external expressions. Check.
 

I questioned Maple's trivial answer because I saw in some textbook something using eigenvalues and eigenfunctions.
I am grateful for the information.
Oliveira.

Yes, but I found the problem:
The problem occurred because I loaded package Physics and with it came the option assumingusesAssume = true (for the assuming command), which caused a conflict with the piecewise function. Unfortunately we have to be careful to avoid these conflicts.

Thank you for your attention and response.

I  am grateful for the information. By the way, can you tell me where the Maple boot file is? I would like to insert some macros in this file.

Thank you,

Oliveira

Thanks for the answer.

Very good. Thank you.

Thank you for your response and attention.

Oliveira

@dharr 

Thanks again.@Carl Love 

Thanks again.@acer 

It worked and thank you very much for your help. Now what if the command had a second argument?. For example:
 x^2-2 x &//eval, x=4
how to do?
@acer 

It worked and thank you very much for your help. Now what if the command had a second argument?. For example:
 x^2-2 x &//eval, x=4
how to do?
@Carl Love