@ecterrab 

"I do not see the roadmap" I am trying to find this.

But these 2 posts below does a good job summarizing the stages to go through to graduate from area 51 and become an official stack exchange web site.

Notice that this is just for graduation phase from area 51. After becoming an official stackexchange site, there is no more any such requirments on how many questions per day, and any such thing. The site then just runs on its own.

https://area51.meta.stackexchange.com/questions/28124/minimum-number-of-people-for-a-successful-proposal

https://area51.meta.stackexchange.com/questions/28183/when-can-example-questions-be-answered

Here is the summary from the above:

There are 3 phases to complete: 1. definitions, 2. Commitment 3. beta.  Maple last time went to Commitment phase only and stopped there.

"A proposal needs 60 followers to complete the definition phase."

"200 committers, at least 100 of which have 200+ rep on any other site, and a high enough commitment score"

"Broadly speaking, you will need a community of at least 300-400 avid users (minimum!) "

"The second hurdle is Commitment where you'll need at least 200 users to "commit" to using the site if we create it. 100 of those users will have to earn at least 200 reputation on other Stack Exchange sites to move the proposal on to the Private Beta."

"Finally, if the proposal makes it to Private Beta, you will have about three weeks to attract enough users to curate at least 150 high-quality questions to become a fully listed public site"

So the bottom line, is having lots of users ready to sign up for it. At least 400 or so users (but with half with high reps, 200+) is all what is needed. From the screen shot above by Acer, there was 120 users commited on last attempt.  (I do not know if there was more after that screen shot was taken). I also rememebr many did not have high reps (i.e. over 200 rep) so those users did not count, and that was one of the main reason why Maple did not make it.

There is also a time limit to obtain this number. I do not know know the time. May be few months or so. Will try to find out.

@ecterrab 

If I remember right, there was a first proposal about 7-8 years ago (any one else remembers?). And then another one about 2 years ago. I forgot now the person who initiated it.  Both were closed.

https://area51.stackexchange.com/proposals/70511/maple 

https://www.mapleprimes.com/posts/207987-StackExchange-Site-For-Maple

They remove the actual proposal web pages once it is closed (too bad) so one can't go visit these in order to use the same good questions posted there and same defintions to avoid having to do all of this again and to see the activitiy that happened. But someone with over 10,000 reputation in Area 51 can still see them. I do not have this high reputation myself in area 51.

I remember having a screen shot of it at one point but can't find it.

To get an idea what is needed for proporsal to successed, here is Mathematica's one from about 7 years ago.

https://area51.stackexchange.com/proposals/37304/mathematica

From https://area51.stackexchange.com/faq

I do not know if a deleted proposal can be "reopened". I think one needs to start one from scratch all over again. I'll try to find out. May be someone here knows.

But before doing any of this, we need to make sure there will be enough interest and more users this time to make it pass. Otherwise the same thing will happen like the last two times.

of course having a Maple stack exchange site will surely benefit Maple greatly.

For one thing, searches will be easier, one can enter Latex directly in the question/answer, finding answers and questions will be easier, there will be a chat room; (Which can really be good for building a community) and commenting will be easier, and the forum is much faster and easier to use and has many more features. 

There is a Maple tag at stack overflow [moderator: stackoverflow, math.stackexchange], but it is hardly used and it is not the same as having own site at stackexchange really, like Mathematica.

But this has been tried before two times allready, and both times it failed to gather enough interest to pass the threshold needed in area 51. It is not clear why that is. (myself voted for it in both cases).  So I am afraid trying a third time, will not give a different result.

@Mariusz Iwaniuk 

I am not familiar with this notation %, what is the difference between 

            f1 := (t, w) -> %invlaplace(1/(s^2*w^2), s, t)

and

            f1 := (t, w) -> invlaplace(1/(s^2*w^2), s, t)

And when should one use %?

ps. I use only worksheet mode.  When I used the second form above, I get OK result for some of the results you show. For example

@ecterrab 

Thank you very much for the quick fix.  

I wonder why Maple does not determine the eigenvalues and eigenfunction with periodic boundary conditions when the IC is missing? The solution given is correct, but not the most general one. What I mean, if Maple found the eigenvalues and eigenfunctions, then the solution should be

But Maple gives

Only when adding IC, does Maple  find the eigenvalues and eigenfunctions

But finding the eigenvalues and eigenfunctions does not depend on the IC being there and can be found separately and independent of what the IC is since those come from the spatial boundary value ODE.

This seems to happen only when the BC are periodic. For non-periodic BC, Maple does find eigenvalues and eigenfunctions OK. Here is an example

pde:=diff(u(x,t),t)=diff(u(x,t),x$2); 
bc:=u(0,t)=1,u(Pi,t)=0;
maple_sol:=pdsolve([pde,bc],u(x,t))

Hopefully in future versions Maple can do the same when BC are periodic.

Please find my hand solution in PDF file attached below for this problem.

Maple Worksheet - Error

Failed to load the worksheet /maplenet/convert/pde_sol.mw .
 

Download pde_sol.mw

sol.pdf

(Unable to insert content of worksheet for some reason)

@ecterrab 

thank you for the additional information about implicit solution. 

I never said the software is random. I only reflect what I see as a user, since I do not know the internals.

It also works with implicit solutions. I mean changing _C1 to C[1] on an implicit solution gives 0. 

ode:=x*diff(y(x),x) = y(x)-x*(x-y(x))*sqrt(x^2+y(x)^2);
sol:=dsolve(ode,y(x),'implicit');
odetest(sol,ode);
new_sol:=subs(_C1=C[1],sol);
odetest(new_sol,ode);

Both calls to odetest give zero above

Here is another example

ode:=x*diff(y(x),x) = y(x)+a*sqrt(y(x)^2+b^2*x^2);
sol:=dsolve(ode,y(x),'implicit');
odetest(sol,ode);
new_sol:=subs(_C1=C[1],sol);
odetest(new_sol,ode);

Both calls to odetest give zero above

fyi, I run both above in Maple 2018 since my Maple 2019 is busy now running a long running program which takes hrs to complete.

But thank you again for the explanation. I am all set now, as I change C[1] to _C1 just in case before using odetest.

@acer 

thanks. Will try to integrate your code above in my program and see if it works. I have 10's of thousands of Maple expressions that I convert to Latex. This issue with `1` is very minor compared to the many other problems with the latex that Maple generates.

@ecterrab 

thanks for the explanation. Now I understand better. But this behaviour do not happen all the time with odetest, otherwise I would have noticed it long time ago. I run thousands of ODE solutions via odetest to check if I get the solution correct.

Only few had this issue that is why I thought there was a problem. 

For example

ode:=-1/2*y(t)+diff(y(t),t) +3*A= 2*cos(t);
sol:=dsolve(ode,y(t));
sol:=subs(_C1=C[1],sol);
odetest(sol,ode)

The above gives 0 even though I changed _C1 to C[1] in the solution.

But it is no problem for me now. I simply change C[1] to _C1 before calling odetest and now it works with no problem

Thanks

@vv 

let me make sure I understand. You are saying given an exact A+B*y'=0 then A/B+y'=0 can no longer be exact? Just by rewriting it, Even if it is the same ODE? 

I'll have to ask the teacher at school about this.

@acer 

You are using `frontend` quite differently from both what I suggested earler and what I put in my answer. Why!?

When I updated my answer, I have not yet seen your answer. I saw your answer afterwords.

As I mentioned, I never used frontend before, and that was my first attempt at using this command. 

@Rouben Rostamian  

Yes. I read that. But notice it says The sign function works for polynomials  and not The sign function works ONLY for polynomials

Also, before that help says The sign function computes the sign of the leading coefficient of expr.

But If the sign function is not the right tool, what else to use?  One thing I thought about  to try is this: convert the expression to a string, and simply look at the first non white character in the string generated to see if it is a "-" or not.  I will try that next.

@Rouben Rostamian  

fyi, There is a bug in the above method.

Download bug_08_21_2019.mw

@ecterrab

None of the textbooks I looked at mention difference between "essential" or none "essential" singular solution.

They say simply that singular solution is envelope of the general solution. One which can not be obtained by specifying specific value for constant of integration in the general solution.

A solution found by specifying a value of the constant of integration is normally called in the textbook a particular solution and not a non-essential singular solution if I understand the Maple term you are using.

So this term non-essential singular solution is something I never heared before.

But in this sense, when I say singular solution, I mean "essential singular solution" using Maple terminology.

Maple does not return "essential singular solution" all the time. For example, for  y(x) = y' x - sqrt(y' a) There is one singular solution, Which Maple does not show. I solved it by hand. (I can post my hand solution if you like also).

Maple returns the general solution only even when using singsol=all

Here is another one from a text book. The book shows the singular solution, which maple does not show. I put a screen shot of the solutioin given from the book for your consideration.  It shows singular solution which Maple does not return even when setting singsol=all.

I do not see how one can obtain the singular solution shown above from the general solution by giving a specific value for _C1? As the general solution are straight lines, while the envelope (the singular solution) is curved.

Thank you for any hints on how to obtain the above singular solution shown in the book.

Download missing_singular_2.mw

@tomleslie 

"However if you are partcularly interested in singular solutions, then it is probably a good idea to make this requirement explicit."

The above does not always work. Here is a case I found where even when using singsol=all Maple does not show the signular solution for the ODE when written in different form (breaking it into two sets of Clairaut ODE's instead of one). There is a problem somewhere why Maple sometimes shows singular solutions and sometimes it does not.

Download missing_singular.mw

@Thomas Richard 

Yes, this is what I did also. I simply forgot to mention it after playing with it for a while.

First thing I do always when using exact solvers like pdsolve or dsolve is convert all numbers to be exact. I do this by habit. Then run the code.