@Carl Love 

This question is somewhat related to my question
http://mapleprimes.com/questions/219357-How-To-Use-ToJet-Command-When-Differential
I am trying every possible way that I learned so far but not getting desired result.

Please help !

Dear Sir

I am performing compositing differetiation of some function and need to compsite derivatives in subscript format without using 'D'. Please see worksheet.

Download Query1.mw

Regards

@tomleslie 

Actually I did those chnages but forget to save the editings before uploading to Mapleprime. Thank you very much for you efforts.

@tomleslie 

The thing that I was doing wrong is only 'I' as complex number in place of 'i'.  Now everything is working fine.
But please see why this symbol 'j' as complex number not creating problem in direct computation ?

Thanks a lot.

List.mw

@Carl Love 

Here is updated file.

[852]_Determining_Equations_Using_Prolongation.mw

@Carl Love 

Here g(u[x]) is actually a function of u[x] and g[u[x]] is derivative of g with respect to u[x].

@ecterrab 

Since my PDE involves function f(u) so removing 'integrabilityconditions = false' is not a better option neigther the "casesplit(DetSys)' solves my purpose of obtaining contraint differential equation for f(u). Anyway 'RosenfeldGroebner' worked for me.

@Adam Ledger 

No matter what other say, he is a pure Russian by heart. What peoples can expect from him any further !!! He has opened almost new field to mathematicians and he left peoples scratching heads for another century just like Poicare did. Let him enjoy his life.

@Adam Ledger 

I think this community is not suitable for asking such questions. You can ask such type of  questions on StackExchange.

@Christian Wolinski 

See Top answer to my question by Preben Alsholm you will see how simple answer he has given. That is exactly I was looking for. More elaborate answer is also given by Carl Love.

@PascalQM Thanks for your help but solution to my problem is better handled with "frontend", see answer given by Prebem Alsholm.

@Preben Alsholm That the way I am looking for. How this frontend works in general way ? Because I have seen it in Maple help but could not understand its real use.

@PascalQM 

That will do but do not want to do in this way. I am looking for alternative and more flexible option so that I can find coefficient in single command line.

@Carl Love 

I must say you use to nail every query.

@Kitonum 

When I export plot in png format by right clicking on plot why color of plot slightly changes ?