I wrote a code example here, because You don't give any. I not a Harry Potter to see and reads OP's  code minds.
Download PDESOL.mw

People here generally like users to post code as Maple code instead of images or TeX, so they can copy-paste it. It makes it convenient for them and more likely you will get someone to help you. You want solve PDE numerically then add the missing parameters,like initial,boundary conditions,concentration of electrons and so on.

thanks a lot@Kitonum 

@Kitonum 

Binary(4);

convert(4, base, 2);#Check

                           [1, 0, 0]
                           [0, 0, 1] ?
 

Maybe this help you:https://www.mapleprimes.com/questions/203465-How-Do-I-WRITE-not-convert-To-A

 Maple does not give any solution because No solution exist in yours case.

Mathematica 11.3 can't compute limit (2) too.

@acer 

Thanks. Exactly that's what I needed.

@vv 

Thank you very much. :)

@vv 

Thanks,but:

plot([f, 'fdiff(f(t), t = x)'], x = 0 .. 10);# Not working ?

plot([f, 'fdiff(f(t), t = x)'], 0 .. 10);# Not working ?

How to do it on  the one plot  not using a display command.? 

@Kitonum 

Thanks ,but i need  solution of my problem with new Interpolation[Interpolate] packges.

Probably exact solution no exist. With Maple 2018 and updated version Physics package version 39 ,Maple return NULL.

Mathematica 11.3 also does not know the answer.

No-PDE_exact.mw

PDE Mathematica.pdf

@ecterrab 

Ok thank for the explanation.

@ecterrab 

In Maple Help:

?DifferentialThomas;

Overview of the DifferentialThomas Package.

When I click on the blue underlined subtitles such as:

ComplementOfDecomposition
Equations
Inequations
IntersectDecompositions
LinearCombination
NormalForm
PowerSeriesSolution
Ranking.
ReducedForm
ThomasDecomposition
Tools

CheckResults
Differentiate
Display
FromJet
Initial
Leader
Reset
RunEncapsulated
Separant
ThomasOptions
ToJet

and more, nothing happens ?

There are no descriptions of these functions ?

@Rouben Rostamian  

Thank you for the good explanation of the matter.