First-timer,

How do I enter a double integral in Maple Learn? The bar has only single integrals. Using parenthesis yields dxdx. I can't use two separate integrals because the second intetral is Int(f(y)dx) not Int(f(y)dy).

Thanks

Mark

Here is my code:

t := 6*Pi; lambda := .1; N := 5; M := sqrt(N(N+1))*exp(I*phi); omegap := 1

eq1:=-2*(n(phi,delta)-N)+(u(phi,delta)-M)*exp(-2*I*omegap*t/lambda)+((z(phi,delta)-conjugate(M))*exp(2*I*omegap*t/lambda)):
eq2:=-2*(1-I*delta)*u(phi,delta)+2*(n(phi,delta)-N)*exp(2*I*omegap*t/lambda)+2*M:
eq3:=-2*(1+I*delta)*z(phi,delta)+2*(n(phi,delta)-N)*exp(-2*I*omegap*t/lambda)+2*conjugate(M):
convert(eq1, rational); convert(eq2, rational); convert(eq3, rational);

f1:=evalc(eq1);f1:=evalc(eq2):f3:=evalc(eq3)
f1 := solve{f1, f2, f3};
with(plots); Impliciplot3([n(phi,delta)], delta = -10 .. 10, phi = 0 .. 2*Pi);

Hi, 

I work with a parameterized ODE whose numerical solution is called sol.
The names of the parameters I get from sol(parameters) are not the same as the initial names I used.
I've been stuck on this problem for more almost two hours and I can't find out if I made a mistake or if it's a Maple problem.

Thanks for your help


 

Download X_is_not_X.mw

Hello,

I have a problem with PDE coupled that I don't know how to solve in the maple.

Are there some analitical/numerical methods to solve the problem?

Any help will be usefull!!

I'm trying to find the interval of convergence for the sum

sum((x-2)^n/((x-2)^n),n=0..infinity)

```

c:=n-> 1/(n^2-1)
   c := proc (n) options operator, arrow; 1/(n^2-1) end proc

s:=x-> sum(c(n)*((x-2)^n), n=0..infinity)
 s := proc (x) options operator, arrow; sum(c(n)*x^n, n = 0 ..

    infinity) end proc

# figure out how to plot this, without making it crash
abs( (c(n+1)*x^(n+1)) / (c(n)*x^n) );
                      | (n + 1) / 2    \|
                      |x        \n  - 1/|
                      |-----------------|
                      |/       2    \  n|
                      |\(n + 1)  - 1/ x |

simplify( % );
                          |  / 2    \|
                          |x \n  - 1/|
                          |----------|
                          |n (2 + n) |

L:= limit( %, n=infinity );
                            L := |x|

solve( L<1, x );
                  RealRange(Open(-1), Open(1))

simplify( s(3) )
                            infinity

```

How do I get it to find the correct interval, which is [1,3] I get the correct radius, which is 1.

I'm able to export Maple documents as LaTeX, but I'm not able to execute them because I can't find the package in

{maplestd2e}

in MikTex.

How do I add this package to MikTex, and by extension, TexnicCenter?

For the Latex code of matrix B, I used the following procedure. But the last column of B is not what we're looking for in the latex code. (There is no problem in the other columns)

Download_Latexcode.mw

restart:
interface(rtablesize=20):
f:=(x,t)->x*t;
g:=(x,t)->x^2*t;
  
B:=Matrix([[x,t,"f(x,t)","g(x,t)"],
         seq(seq([i,j,f(i,j),g(i,j)],
                 j=0.125..0.875, 0.25),
             i=0.125..0.875,0.25)]):
B[1,..]:=map(p->nprintf(`#mi(%a);`,p),B[1,..]):
B[2..,4]:=map(p->nprintf(`#mn(\"%1.2e\");`,p),B[2..,4]):
 
 

Lat:=proc(M::Matrix,
          {output::{NoUserValue,identical(string)}:=':-NoUserValue'})
  local m,n,S;
  (m,n):=op(1,M);
  S:=cat(" \\begin{tabular}",
         "{|",seq("c|",i=1..op([1,2],M)),"} ",
         "\\hline ",
         seq([seq(sprintf("$%s$ & ",latex(M[i,j],':-output'=string)),j=1..n-1),
         sprintf("$%s$ \\\\ \\hline ",latex(M[i,n],':-output'=string))][],i=1..m),
         "\\end{tabular} ");
  if output=':-string' then
    return S;
  else
    printf("%s",S);
    return NULL;
  end if;
end proc:
Lat(B);

The input

f(x) := x^2;

n := evalf(int(f(x)^2, x = 0 .. 1));

f(x) :=  f(x)/n;

plot(f(x), x = 0 .. 1)

leads to the error

Error, (in f) too many levels of recursion
I need to reassign the function as itself divided by n that depends on the old f...

A piece of code like this is supposed to be inside a loop, so creating f_new(x):=f(x)/n doesn't solve the issue.

If it was a cpp code I'd write something like f(x)/=n for every x. How can I do it in Maple?

Thank you in advance for you answers!

with(plots, implicitplot);

eqn := (1 + ln(x))/x = 0;

plot1 := implicitplot(eqn, x = -10 .. 10, y = -10 .. 10)

I'm trying to plot this equation, however no lines are showing up on the graph at all. Am I doing something wrong?

The interval I set seems to be correct, double checked it in other software

Would like to export a list into a text file

when I tried , it show ... 1234 items... , can not export a whole list into text file.

[[[0,0,0,0]], [[0,0,0,0]], .....]
thousands of [[...]] elements

This is an issue I had for long time. Though to ask about it.

Any one who used Database[SQLite] in Maple probably know this.  I'd like to do kernelopts('assertlevel'=2): but this does not work when using Database[SQLite] as it raises assertion failed, due to the way data is read from database and converted to Maple variable.

It happens at the statement 

         variable_to_read := Database[SQLite]:-FetchAll(stmt); 

For an example, the table I have in sql, has many fields. some are strings and some are integers. Lets say I want to read field called run_it corresponding to rowid I enter. So I do this in Maple

local run_it::integer;
.....
counter :=1;

stmt := Database[SQLite]:-Prepare(conn, cat("SELECT run_it FROM PROBLEMS WHERE rowid=",convert(counter,string),";"));    

run_it := Database[SQLite]:-FetchAll(stmt); 

The assetion error happens at the second call above. 

Error, (in dsolver_test:-MAIN_STEP) assertion failed in assignment, expected integer, got Matrix(1, 1, {(1, 1) = 1}, order = C_order, attributes = [source_rtable = (Array(1..1, {(1) = 1}, order = C_order))]) 
 

Once I remove kernelopts('assertlevel'=2): everything works fine with no problems at all. So I been running my program for more than a year now without the assert set.

Since I have hundreds of  such calls, and I do not think try/catch will work here, any one knows of a way to handle this, so I can turn on assertlevel to help catch any other problems some where else in the program, and still use SQLite ?

I could make an example if needed. I would need to create new database file and so on. This will take time.

Maple 2020.2

ps. Database[SQLite] works very well and very fast. I am surprised how fast it reads the data. few thousands records, each is 25 fields, and it does it in few seconds. Good implementation.

Edit

I found that by removing all the type specification on my Maple variables, that I read the SQL data into using FetchAll(stmt);  it now works!

So I am able to now use kernelopts('assertlevel'=2):

So intead of doing  

local local run_it::integer;  and then call SQL, I just now do  local run_it; with no type.  I had to remove the type on many such variables I had.  Now no assertion error any more during the SQL calls.

This works for me for now. I should have done this long time ago, I just did not think about it before. I would have liked to keep the type here.

Edit: I see answer below that allows me to do this by changing assert level just for the call to SQL which is good solution.

In Maple 2020.2, and after I changed to interface(warnlevel=4); then once in a while, I now see this message 

                                  Warning, persistent store makes readlib obsolete

followed by name of the file and the line number. It always happen at calls to timelimit(the_time_limit,:-dsolve(....

It seems harmless so far, as I have not seen any side effect.

I googled and the above, and see few places where it shows up, but no clear explanation what it is and what it means. But the messages I saw at google are a little different. They look like this

               WARNING: persistent store makes one-argument readlib obsolete

While the one I get is a little different as you can see. (no one-argument in it)

I am using my own package in .mla file during running the code if this makes any difference.

Is there any place where it explains what this means and why it happens sometimes? Sorry, can't make MWE, since it seems to happen at random. But I noticed it always happens at call to dsolve when I saw it.

Maple 2020.2

Physics 884

Windows 10
 

Note: If I remove the cosh from P1 then everything works fine.

Download DP_sheet_0.1.mw

I'm trying to make a table of values as a data table.  The problem is that it's making more rows than loops, I'm not able to make an empty DataFrame, and that I have to add an extra row to align the values, so I need to remove a row, and change the indexes.  Any help with making data tables work properly, would be greatly appreciated.

```

newt := x -> evalf(x - f(x)/D(f)(x));

f:= x -> x^6-2; # function to analyze

rt[0] := 1.5; #x0 value

n_error[0]:=1.5-newt(1.5): #error of first estimate
     

DF := DataFrame( <x|n_error>):# create a dataframe to store estimates, and error rates
for count from 0 to 10 do; nerror[count]:=abs(x[count]-x[count-1]);    rt[count]:=x[count-1];
x[count + 1] := newt(x[count]); DF:=Append(DF,DataSeries(<rt[count]|nerror[count]>),mode=row);    
end do:

NewtonData:=DataFrame(Remove( DF, 2, mode=row)):
NewtonData

```

In the below paper 

ODEs are solved by using Matlab Software

Is it possible to solve this in Matlab software?  [I think you mean Maple!--Carl Love]

I have attached the Article

j.physa.2019.123959.pdf