I presume your web browser has been set up to block popup windows.  You should place www.mapleprimes.com on the list of sites from which popup windows are allowed.  If you're using Firefox, choose Tools, Options..., Content, click on the Exceptions... button to the right of "
"Block popup windows", and www.mapleprimes.com and click Allow. 

Hmmm... it seems there's a difference between Worksheet mode and Document mode.  In Worksheet mode, math embedded in text in the way I mentioned is non-executable, in Document mode it is executable.  I have not been able to find a way to make it non-executable.

Hmmm... it seems there's a difference between Worksheet mode and Document mode.  In Worksheet mode, math embedded in text in the way I mentioned is non-executable, in Document mode it is executable.  I have not been able to find a way to make it non-executable.

_F1 and _F2 are arbitrary functions.  Any (twice-differentiable) functions of one variable will do.  Note that pdsolve does not always find a general solution: not every solution will necessarily be of the form it returns (although in this case it would be true in a simply-connected domain: look up harmonic conjugate).

As far as I know there is no Maple command to find harmonic functions with given boundary conditions (look up Dirichlet problem).  Depending on the shape of the region, you may be able to use Fourier series.

You can reference and manipulate spreadsheet data using Maple commands.  This is what GetCellFormula, GetCellValue, GetFormulaeMatrix, GetValuesMatrix, SetCellFormula and SetMatrix are for.  See ?examples,spread.

You can reference and manipulate spreadsheet data using Maple commands.  This is what GetCellFormula, GetCellValue, GetFormulaeMatrix, GetValuesMatrix, SetCellFormula and SetMatrix are for.  See ?examples,spread.

Hmmm...   I seem to have aswered the question you asked, but not the one you meant.

The actual problem is not to stop a line of code from executing, it's to stop the Spreadsheet from being affected by the !!! button.  When you press !!!, each execution group in the worksheet is executed, which involves the previous output of that execution group being replaced by new output.  If the command was CreateSpreadsheet, that means the old Spreadsheet is destroyed and a new one created.
Commenting out the CreateSpreadsheet command doesn't prevent the old Spreadsheet from being destroyed, it just prevents a new one from being created.

I think the only way to prevent this is not to produce the Spreadsheet as the output of a command.  Instead, use the menu items Insert, Spreadsheet.

Hmmm...   I seem to have aswered the question you asked, but not the one you meant.

The actual problem is not to stop a line of code from executing, it's to stop the Spreadsheet from being affected by the !!! button.  When you press !!!, each execution group in the worksheet is executed, which involves the previous output of that execution group being replaced by new output.  If the command was CreateSpreadsheet, that means the old Spreadsheet is destroyed and a new one created.
Commenting out the CreateSpreadsheet command doesn't prevent the old Spreadsheet from being destroyed, it just prevents a new one from being created.

I think the only way to prevent this is not to produce the Spreadsheet as the output of a command.  Instead, use the menu items Insert, Spreadsheet.

To prevent execution of a line of code, "comment it out" by inserting # at its start.

To prevent execution of a line of code, "comment it out" by inserting # at its start.

Change the Format to "formatted" instead of Normal.

restart;

w:= 4:

w1_lst:=NULL:

for k from 1 to 10 do

  for h from 1 to 20 do

    for a from 4 to 15 do

      w1:= a + h:  #h, not hk

      w1_lst:=w1_lst,w1:

       if  w1< w then w:=w1:

       else w:= w:  #redundant

       end if:

    end do:

  end do:

end do;

w1_lst;

Change the Format to "formatted" instead of Normal.

restart;

w:= 4:

w1_lst:=NULL:

for k from 1 to 10 do

  for h from 1 to 20 do

    for a from 4 to 15 do

      w1:= a + h:  #h, not hk

      w1_lst:=w1_lst,w1:

       if  w1< w then w:=w1:

       else w:= w:  #redundant

       end if:

    end do:

  end do:

end do;

w1_lst;

Or if you only want to allow Quantity objects but not any other functions, you could say

dWdt := proc(t::{float, specfunc(anything,ScientificErrorAnalysis:-Quantity)}) ...

Or if you only want to allow Quantity objects but not any other functions, you could say

dWdt := proc(t::{float, specfunc(anything,ScientificErrorAnalysis:-Quantity)}) ...

To get both symbols and connecting lines, I think you need to use separate pointplot commands (or a plot and a pointplot), and then you can combine them using display.  Thus:
 

> display([pointplot(stressStrainData, connect=true, colour=red), 
           pointplot(stressStrainData,  symbol=circle, colour=blue)], labels=[engrStrain, engrStress]);