@dharr 

hi, dharr:

   it worked, thanks you for help.

best regards

@Rouben Rostamian  

I followed your suggestion:

assigning numerical values to all the parameters, evalaute your solution versus Maple's,

and indeed, they are actually giving the same numerical value. just the maple answer is more complicated and more general.

thanks for your help and wish u a nice day.

best regards

@Rouben Rostamian  

hi, Rouben:

   thanks for your reply. 

   Yes, it's my mistake to consider it as a linear equations.(i normally only solve linear equations...so it's thoughtlessness to use LinearAlgebra package)  Equ4,5,6,7 are all non-linear equations as you mentioned.

  In my 2nd solution, I use solve command. 

and get the results:

even I assume the known parameter: ZL,ZT, theta, I1,I2 are all real number, still can not get a simple answer.(alsways with RootOf)

any idea how I could get the 'right' results as follows?

here is my modified .mw. please take a look.

question_DHT_2nd.mw

thanks for your help

best regards

@Carl Love 

hi,carl:

when i dig into your code. I notice you are using this from your code to replace the subindex to normal letter.

such as:

  -> really nice and blown my mind.

S:= subsindets(
    simplify(solve(Eqs, Svars)),
    patindex(anything),
    n-> cat(op(0,n), op(n))
):

i must admit the complexity of this long command is out of my ability as a newbee.

could you please explain why patindex(anything),  n-> cat(op(0,n), op(n) can do such replace?

I would also hope you can recommand some links for me to learn those parttern match replacement, which is extremely useful.

 (I checked the help but not geting straightforward answer)

thank you for providing such good solutions and open a new door for newbees like me.

best regards

I just find a better one.

only use the latexlive  :https://www.latexlive.com/

enjoy the new flow!

@Carl Love 

inspired by you, I re-write some expression and use the recommended simplify command and directly get the final answer without verbose substitude process.

here is the worksheet.

reply_CarLove.mw

thank you for your kind help and wish you a good day.

best regards

@tomleslie 

thank you for joining this topic and providing such a elegant solution. i like it

@Carl Love 

thank you so much for joining this topic and provide a concise way to do this. 

I am digging into your answer with gratitude.

@mmcdara 

thank you so much for your detailed explanation. I am digging into your answers with deep appreciation.

it's my first threads posted here and I am more motivated to use maple since people here are so helpful.

@Preben Alsholm 

hi, thank for your reply.

the way that you create the .mpl file works for me.

initially, I use the flow described in the user manual chapter 11 :Writing Packages -> A Simple Example

(quote:In the example above, the definition of the module SomeTools have been put in a file called SomeTools.mpl in the samples/ProgrammingGuide/ directory of your Maple installation) )

I modified the SomeTools.mpl and directly use it in my script .mw. it's not working. after I check, the SomeTools.mpl format is totally messed up. so I use your idea: exported it as an mpl file using the menu.

then the exported .mpl is good to use.

thank you for providing a such a nice way to generate the .mpl file