## conversion of Prolong output...

In DifferentialGeometry package, let P be the output of Prolong applied to a Transformation.

How to extract each identity/equation from P?

Is there a way to convert P to an array of equations?

## How to do dchange OLD=NEW where NEW contains para...

I am learning how to use dchange in Maple. I can do  something as dchange(x=t^2) OK, but I need to do dchange(x=t^n) where "n" is meant to be a parameter that I can later use subs on to set it to any number I want.  But I do not know how to tell Maple that "t" is the new variable and that "n" is meant to be used as constant or parameter.

As an example, this works

```n:=2;
ode:=x^2*diff(z(x),x)=0;
PDEtools:-dchange({x=t^n},ode,{t})
```

But this does not work

```n:='n';
ode:=x^2*diff(z(x),x)=0;
PDEtools:-dchange({x=t^n},ode,{t});
subs(n=2,%)
```

It used "n" above as new variable. So the dependent variable which was z(x) became z(t,n).

So I need to tell Maple that "t" is the new variable only and not "n" as well.

Is it possible to do this in Maple?

Maple 2019 on windows.

## Double integral...

Hi,

I compute a double integral, and I would like to change the order of integration ( of course we take into account the domain of integration, that must be changed), but unfortunately I have two different values instead the same value.

order_integration.mw

Note that I the code if I put t_0=0, I get the same value. Bur for other values of t_0, i havent the same value.

## Maple displays incorrect float....

Maple gives me the incorrect answer to the hundredth place. (arithmetic.mw)

>15000*(1+.06/365)^(10*365)
>                        27330.47804

I tried using an exact fraction 15000*(1+(6/100)/365)^(10*365) as well.

## Drawing together a function of two variable and it...

How can I draw together the function f(x,y)=(x.y^2)+1 and its tangent plane at the point (2,1,f(1,2)) in each of the following rectangles?

(Note that the equation of the tangent plane at the given point is z=x+4y-3)

a. 2<=x<=3 and 1<=y<=3

b. 2<=x<=2.1 and 1<=y<=1.2

c. 2<=x<=2.01 and 1<=y<=1.02

## pdsolve 2d EQUATION...

I can  this equation.

 >
 (1)
 >
 (2)

Boundary condition:

 >

#####################################

INITIAL CONDITIONS:

 >
 (3)
 >

## dissolve/numeric provides the solution but plot do...

Greetings everybody!

I am facing a strange problem. Dissolve/numeric seems to provide a solution and gives no error. However, when I try to plot the solution, Maple gives an error. Please guide me how to get rid of this error and how to plot the graph?

Thanking in anticipation.

fracmprime.mw

## What is the problem and how to solve it,thanks...

with(Groebner);

Jugdement := proc (F, P)

local f, N1, N2, i, j, k, q, LTF, LTPj;

N1 := nops(F); N2 := numelems(P);

for i to N1 do

LTF := LeadingTerm(F, plex(w, t, s, x, y, z));

for j to N2 do

LTPj := LeadingTerm(P[j], plex(w, t, s, x, y, z));

f := divide(LTF[2], LTPj[2], 'q');

if f = true then

k := j;

break

end if

end do;

if f = true then

break

end if;

if f = false then

F := F-LTF[1]*LTF[2]

end if

end do;

return k, f, q, P[k], LTF[1]

end proc：

F := x^2+y^2+z^2;
2    2    2
F := x  + y  + z
P := {z, x*z, y*x};
P := {z, x z, y x}
Jugdement(F, P);
Error, (in Jugdement) illegal use of a formal parameter

I want to know what is the problem?

## riemann curvature tensor maple and also need to ...

i) D(X,Y) , D(X,Z) ,D(Y,Z) COVARİANT DERİVATİVE ?

İİ) [X,Y] LİE OPERATOR ?

İİİ) R(X,Y)Z = D DZ - DDZ - D[X,Y] Z

## How to improve menu speed in Maple 2016...

How to improve menu speed in Maple 2016?

I am using Maple 2016, when I right click the equation, it really takes a long time to show the menu. It seems that the CPU usage and Memory usage is low, it should be fast as it is only a showing menu action, what's wrong with that?

## Wrong information in a help page...

Hi,

The help page TimeSeriesAnalysis, ExponentialSmoothingModel contains an error.
The command that generates the output (7) should be

PS : there is no tag relative to TimeSeriesAnalysys

## Express (cos^6)*t in terms of sines and cosines mu...

Hello! How would I do the following question using the maple program? I am not sure about the syntax. Thank you!

Express (cos^6)*t in terms of cosines and sines of multiples of t for

(cos^6)*t = a*cos(6*t) + b*cos(4*t) + c*cos(2*t) + 5/16

Where a = ?, b = ?, and c = ?

## How to create Loop and Multiple edges of Graph u...

Hello!
As we  known, in Graphtheory , a loop is an edge that joins a vertex to itself (for example  fig1 vertex1) and multiple edges (for example Fig2）are two or more edges that join the same two vertices.  But in Maple,  G := Graph({{a, b}, {a, c}, {b, c}}). The Edges(G) function returns a set  (not list )of the edges of G.  So, for example I can't create loop{1,1} by G:=Graph({{1,1},{1,2},{1,5},{2,5},{2,3},{5,4},{3,4},{4,6}})   . But in my research, I consider a graph which exist loops or multiple edges. I want to create  it  .How should I do?  Thanks in advance.

my code like this

with(GraphTheory):
G:=Graph({{1,2},{1,5},{2,5},{2,3},{5,4},{3,4},{4,6}}):
G:=Graph({{1,1},{1,2},{1,5},{2,5},{2,3},{5,4},{3,4},{4,6}}):DrawGraph(G,style=spring);
G2:=Graph({{1,2}}):
DrawGraph(G2);
G3:=Graph({{1,2},{1,2}}):
DrawGraph(G3);

## How to use pdsolve?...

This may be a stupid question, but I am having elementary trouble with pdsolve.

I have the following pde system:

PDE:=[diff(f(x,xp),x)=-(1/2)*(L*xp+2*x)*kl,diff(f(x,xp),xp)=-(1/4)*kl*L*(L*xp+2*x)];

Trying to solve it:

pdsolve(PDE)

I get this error message:

Error, (in pdsolve/sys) too many arguments; some or all of the following are wrong: [{f(x, xp)}, handlenonrationalfunctionsofdependentvariables = false]

I don't understand any of this; can someone enlighten me?

TIA

M.D.

pde.mw