MaplePrimes Questions

I would like to compute the function 

                       f(x) := exp(x) * HeunC(2*x, 1/2, -1/2, -x^2, 1/8, 99/100)

for very large real values of x. However, in the following plot it can be seen that there are already strong numerical instabilities for x>33. What can I do to reach more stability for large x? Or, does somebody know how to get a closed form asymptotic expression for large x?

 

I am working on a simple set of notes for students. Much of the on-line stuff is either out-of-date or too complex.

Here is the problem I wish to show

A corpse was found in a room with an ambient temperature of 64°F. The body temperature on finding the corpse was 75°F; one hour later it was 73°F. Use Newtons Law of cooling to find the time of death.

Here is my solution. I realise the assignment to variable cool is not used. Please tell me any suggestions for improvements.

many thanks


Hi,


When you do this a := plot(1/x, x=0..1);  the figure contains a "smart" graph which extends roughly from 0 to 30 in the vertical direction.
(no discont=true nor smartview=false used here, numpoints set to its default falue)

If you use plottools:-getdata(a); you find that the vertical range is about  0..1800.
It seems to mean that smartview=true (the default setting) overrides the range determined from the values of discont and numpoints?
 

My question is: Is it possible to retrieve the vertical range that plot uses when it displays the graph?
 

Dear all,

I need your help to compute the multiplicative  group generated by the following two matrices.

A :=  Matrix(2, 2, [[2, 0], [0, 1]]) ;

B := Matrix(2, 2, [[1, 1], [0, 1]]) ;

 such that A.B different to B.A

many thanks

 

Hello Dr/Pof/Colleague

Please help me on the ODE BVP problem

my target i want RUN double loop


 

restart

with(plots)

b := 0; c := 0; k[1] := 1; k[2] := 0; Un := 0; d := 0

Eq1 := (101-100*lambda)*(1+a*phi(eta))*(diff(f(eta), `$`(eta, 3)))+(diff(f(eta), `$`(eta, 2)))*(f(eta)+g(eta)+a*(diff(phi(eta), eta)))-(diff(f(eta), eta))^2+k[2]+Un*(k[2]-(1/2)*eta*(diff(f(eta), `$`(eta, 2)))-(diff(f(eta), eta))) = 0

(101-100*lambda)*(1+a*phi(eta))*(diff(diff(diff(f(eta), eta), eta), eta))+(diff(diff(f(eta), eta), eta))*(f(eta)+g(eta)+a*(diff(phi(eta), eta)))-(diff(f(eta), eta))^2 = 0

(1)

Eq2 := (101-100*lambda)*(1+a*phi(eta))*(diff(g(eta), `$`(eta, 3)))+(diff(g(eta), `$`(eta, 2)))*(f(eta)+g(eta)+a*(diff(phi(eta), eta)))-(diff(g(eta), eta))^2+k[2]+Un*(k[2]-(1/2)*eta*(diff(g(eta), `$`(eta, 2)))-(diff(g(eta), eta))) = 0

(101-100*lambda)*(1+a*phi(eta))*(diff(diff(diff(g(eta), eta), eta), eta))+(diff(diff(g(eta), eta), eta))*(f(eta)+g(eta)+a*(diff(phi(eta), eta)))-(diff(g(eta), eta))^2 = 0

(2)

NULL

Valpha := [0, .1, .2]; Va := [0, 0]

etainf := 100

bcs := (D(f))(0) = k[1], (D(g))(0) = alpha, f(0) = 0, g(0) = 0, (D(f))(etainf) = k[2], (D(g))(etainf) = k[2]

(D(f))(0) = 1, (D(g))(0) = alpha, f(0) = 0, g(0) = 0, (D(f))(100) = 0, (D(g))(100) = 0

(3)

dsys := {Eq1, Eq2, bcs}

for j to 2 do for i to 3 do a := Va[j]; alpha := Valpha[i]; dsol[j][i] := dsolve(dsys, numeric, continuation = lambda); print(alpha); print(a); print(dsol[j][i](0)) end do end do

Error, incorrect number of arguments to _Inert_FORFROM

"for j from 1 to 2 do   for i from 1 to 3 do a:=Va[j]; alpha:=Valpha[i];  dsol[j][i]:=dsolve(dsys,numeric, continuation=lambda);  print(alpha);    print(a);  print(dsol[j][i](0));  od  end"

 

NULL

 


 

Download 3DAKc2alpha.mw

Hi all,

I need any help for the following question:

restart;
H :=n ->sum(1/k, k = 1 .. n) ;

If you computational devices has only 16 decimal points of accuracy, does computing H(n) for n greater than 10^16 give  any information about the series;

Many thanks

Hi,

     I am new to Maple and my task is to find an analytical solution of Lateral Vibrations of Beams. Even though I referred this forum to get an idea about solving a fourth order ODE bvp,I still couldn't find the solution. Although a non trivial solution exists for this case, Maple is still returning a trivial output(i.e the determinant is not returning zero). I need to find the value of constants C1 to C4 but I am unable to understand what the error is. I have attached the file containing my current solution below.

SOP2.mw

Any help will be appreciated,

Kind Regards,

Ajay

 

 

how can i determain the drawing dimensions ( length and width), if i want to draw two graphs of the same dimensions?

let
expression := {{a*x}, {{(b*y)}/3}, {a*b}, {log(x+y)}, {3*x}};

I would like to convert the above expression as
 

requiredForm :={a*x, (b*y)/3, a*b, log(x+y), 3*x};

I observed that the function convert can do some convertion but have to use second argument + or *. which causes unstable results.

One method I found is to convert the expression to string and remove "{}" using StringTools:-Remove function.
I would like to know if its possible to do with out converting to String.

result:= convert(expression, `+`);

                                    /1      \              
  
result:= {a b} + {a x} + {3 x} + { - {b y} } + {ln(x + y)}
                                    \3      /            
  

is there anyway I can get the requiredForm

I wanted to investigate this sum. can someone please help me identify why my code is producing the erroraneous output of 1/2 for every number, despite everything aside from the final computation being as expected.

 



Maple Worksheet - Error

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

Download MAPLEHELP.mw

With(group)

a:=[[seq(I,i=0..5)],[seq(I,i=6..8)]]

mulperms(a,a)

array out of range 

according to book, is this calculation?

how to calculate like the book do?

 

i use function 

https://www.maplesoft.com/applications/view.aspx?sid=154192&view=html

but not work

A list must have only 7 one and 50 zeros

length of list is fixed and equal 57

how to list all combination above?

Dear all,

Can anyone help me to adjust the plot data containing (10^-xxxxxxxx)

EX: [3 10^-3967, 5 10^-1924, 4 10^-7315...................]

Thanks in advance.

I am developping an algorythm in which I need to obtain a 3D plot and its respective colorbars. As far as I know, Maple does not have a function with includes such a colorbar automatically (like Matlab, for example). So, I have had to get 3D plot and colorbar separatelly, as independent plots. It has worked fine, but now I need to export such graphics as EPS files, which imply merging them as a single graphic.

Here is a small example, where I try to put such graphics inside a table for then exporting it as EPS:

restart:

with(plots):
with(DocumentTools):

graph:= plot3d(x^2+y^2, x = -10..10, y = -10..10, colorscheme = ["zgradient", ["Red","Blue"]]):

grad_min, grad_max:= (min, max)(op([1,3], indets(graph, specfunc(anything, GRID)))):

colorbar:= densityplot(axis_z, axis_x = 0..0.1, axis_z = grad_max..grad_min, style = patchnogrid, size = [100,250], axes = boxed, tickmarks = [0,10], labels = ["",""], colorscheme = ["zgradient", ["Red","Blue"]]):

tab:= Tabulate([graph, colorbar], exterior = none, interior = none, weights = [4,1]):

 It has not worked, though. Can anyone suggest a solution for that? I need to export both graphics as one single file, preferably EPS, because of its high resolution.

Hello! I am using Trace procedure from LinearAlgebra package and I also want to use Trace placeholder in conjunction with evala (two different procedures with the same name). If I load the LinearAlgebra package, then the Trace placeholder will not work.

The only solution I found is to avoid loading the LinearAlgebra package and call each function like LinearAlgebra[Trace](Q). But this is very tedious (I use many functions in that package), and also if some other user uses my code, he might have already loaded the LinearAlgebra package.

Is there any way to rename a command inside the package when loading it, or any other workaround?

Thank you!
Santiago

 

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