Got a lot of worksheets who are not complete anymore once opened in maple 2020

It can be only opened with a old version of Maple
Can it be imported in Maple 2020?

example 

Dynmod03.mws

Is there a way to verify the following Fourier transform property: F[f(x) exp(i b x)](k) = F[f(x)](k − b)? This is what I tried:
 

Download First_Shifting_Theorem.mw

Is there a way to specify options or something to change the definition of fourier and invfourier to have a 1/sqrt(2Pi) factor instead? I don't want to manually multiply the result by 1/sqrt(2Pi) every time in case I forget to do it and it leads to a mistake in the future.

Dear all,

Please I want only 8 points to show on this curve, how do I specify it?

plot(ln(1+sin(Pi*x)), x = 0 .. 1, legend = numerical, style = point, symbol = box, color = blue, symbolsize = 15, numpoints = 8);

Thank you all and kind regards.

Please do keep safe amidst this global pandemic.

I would appreciate to know how to compute the following in Maple:

Sequence of distinct primes (starting term is 2) such that each subsequent term is the smallest prime not yet seen whose leading digits and the sum of the digits of the previous term are the same. It starts: 2,23,5,53,83,11,29..
 

it should be interesting to see which primes with first digit 3 appear (given that 3 is not a term). I would also like to be able to change the first term (eg to 3).

Best regards

David.

Found in old studymaterial about Loka-volterra ode 

dsolve({D(N)(t)=r*N(t)-k*N(t)^2,N(0)=N[0]},N(t));

Seems to me not logical notation to use a D operator  : D(N)(t)  for this ode : makes it unneeded complicated this notation..or do i miss something?

Please can you help me in resolving this error?

Here is the codeOptimal_control_model_of_DF_and_LP_2.mw

Hi all, I have a linear equations 31 variables, I want to solve for m[i] >=0. Someone can help me, thank you very much.

In reference to the nice application: https://www.mapleprimes.com/posts/209845-Dataframes--Looking-For-A-New-Flashlight by @Christopher2222 ,  my question is: 

is there a simple way to sort primarily by one column, but if two elements possess identical values, then using a second column to determine the order? For example, what if we wanted to sort the flashlight dataframe primarily by "B-type" but use a subsort by "Minutes". 

I wrote a function which used recursion. It worked fine for small dataframes, but was painfully slow with a multi-thousand element spreadsheet.

Hello,

I have a nonhomogeneous heat conduction problem, where the thermal conductivity, the density, and the specific heat of the
material are piecewise functions.

The thermal conductivity derivative has a discontinuity that causes a problem in the pdsolve command (see the first test).

To avoid this problem, I did a second test where the product rule was calculated directly.

Is there a better way to deal with this problem?

thank you

problem.mw

Dear Maple community,

I am trying to import from a .csv (or .xls) a matrix, whose symbolic elements have subscripts of a type "a[1, 2, 3, 4]" (i.e., datatype=indexed). However, when I enter "ImportMatrix(csvFile, datatype = indexed)", I receive an error message "Error, (in ImportMatrix) unable to store '0' when datatype=indexed". I would highly appreciate your help with importing an indexed matrix. Thank you.

Are there any established (or not established but cool) methods to exchange data between different worksheets or workbooks?

Actually there are 2 questions.

1. If I have 2 different worksheets or workbooks open in Maple, and want to exchange data between them.
2. One workbook, but different worksheets in the same workbook.

I am currently working on a project that generates a set of matrices and I want to find their eigenvalues, but using the inbuilt Maple engine takes too long. The problem is that whenever I try to use the Matlab[eig] command I get the error:

Error, (in Matlab:-setvar) unable to store '-3.*Re(X)' when datatype=float[8]
I found out that solving symbolic matrices in MATLAB requires first defining symbols with the "sym" command but I've been unable to do that in Maple.

why   print(lastexception);  gives `[Length of output exceeds limit of 1000000]` while just doing lastexception; gives no problem?

restart;
eq:=x*y*p = y^2+x*(4*x^2+y^2)^(1/2);
try
   sol:= timelimit(20,`assuming`([solve(eq,y)],[real]));
catch:
   print(lastexception);
end try;
lastexception

I know one should use something like

print(StringTools:-FormatMessage( lastexception ))

But I do not know why print(lastexception) gives the length exceeds error. 

whattype(lastexception) gives exprseq

Maple 2020.1

In this post https://math.stackexchange.com/questions/1196194/asymptotic-behaviour-of-frac1x-1-frac1x2-1-frac1x3-1-cdots

this sum is evaluated in the answer to be

I cannot see how to use eularmac to get this answer as x approaches 1.

Maybe using

ge := `assuming`([sum(1/(x^k-1), k = 1 .. infinity)], [k::integer])then something like

eulermac(ge, limit(ge, x = 1), 3)