@henrylyl 

If you define pG:= Array(1..3) followed by pG:= foo, then pG is no longer an Array; it becomes whatever type of object foo is. In your code foo was a list. If you use an index, as in pG[1]:= foo, then pG is still an Array.

In your example above, your Array declaration is wrong. It should be expr1:= Array(1..2, [x^2, x]), which can be abbreviated to Array([x^2, x]). Effectively the same is expr1:= < x^2, x >.

@henrylyl My experimenting shows that the option useunits= [Unit(A), Unit(B)] only affects how the axes are labelled. It does not convert the units, like you said. You can wrap the expression being plotted with a convert command.

@henrylyl 

A^%T means the transpose of A. I used it to convert a column vector to a row vector.

The shortcut to create a row vector is < x | y | z >. In prefix form that would be `<|>`(x,y,z).

If you had made pG in the same manner as G, then the code to display the Array of plots would be simply

display(< display~(G), display~(pG) >);

But the way that your code was, pG was a list, not an Array.

You could guess at the general form of the curve and then apply regression through Statistics:-Fit. Can you post a worksheet with the plot so that I can extract the data from it?

@henrylyl I don't know about the units conversion in plots. The answer may be on the help page ?plot,units . There is a lot of information there, and I don't fully understand it yet. I need to do some experiments.

Regarding your other question about displaying the array of plots, it can be done like this:

display(< display~(G), display~(< pG[] >)^%T >);

Do you have a numeric value for Pr?

Do you have any initial or boundary conditions? You'll need eight.

@bastorer 

It should work the way that you describe. But if Array2:= Copy(Array1) does not give an error message, then you can't be using ArrayTools:-Copy. Can you duplicate the situation?

@Preben Alsholm That works!

@bastorer

Array2:= Copy(Array1);

is not valid syntax for ArrayTools:-Copy. You must have another package loaded that has a Copy command.

@henrylyl The file link works now.

@Preben Alsholm It doesn't work recursively. Example:

restart:
Array1:= Array([Array([1, 2]), Array([3, 4])]):
Array2:= copy(Array1):
Array1[1][1]:= 11:
Array1;
Array2;
              

That was asked and answered 10 days ago, probably by a classmate of yours. See here.

@Markiyan Hirnyk 

I see your point. I wonder why the presence of r with no assumptions makes Maple think that it knows the integral.

@henrylyl File didn't attach. Try uploading again please.