Question: 1D Heat equation with Neumann B.C. Implicit scheme

Hello all!

I have to solve 1D Heat equation with Neumann B.C. using implicit scheme.

I have: 

I have my code in Maple for the solution of this problem using explicit sceme for Neumann B.C.. And I also have the solution of the problem using implicit scheme(but for Dirichle B.C.).

implicit_method_Dirichle_B.C..mws
explicit_method_Neumann_B.C..mws

I know that my Neumann B.C. for implicit scheme will be written like this.
I determined the ghost points and then got the final view of the B.Cs.:

But I can not imagine how I should put my Neumann  B.C. for implicit scheme in the code. 

Please, help me! I will be very grateful!

Please Wait...