Maple Questions and Posts

These are Posts and Questions associated with the product, Maple

Hi!

Somebody know how Maple computes (numerically) the values of the Z function? That is, if we run the command evalf(Z(3)), How compute Maple this number?

Many thanks in advance for your comments.

I am having trouble calculating exterior derivatives for one forms, maple does not seem to recognize them as one forms.

 

Delta := -2*M*R+R^2+a^2

Sigma2 := (R^2+a^2)^2-Delta*a^2*sin(Theta)^2

rho2 := R^2+a^2*cos(Theta)^2

z := 2*M*R/rho2

interface(typesetting = extended)

with(DifferentialGeometry); with(Tensor)

DGsetup([T, R, Theta, Phi], BlackHole, verbose)

`The following coordinates have been protected:`

 

[T, R, Theta, Phi]

 

`The following vector fields have been defined and protected:`

 

[_DG([["vector", BlackHole, []], [[[1], 1]]]), _DG([["vector", BlackHole, []], [[[2], 1]]]), _DG([["vector", BlackHole, []], [[[3], 1]]]), _DG([["vector", BlackHole, []], [[[4], 1]]])]

 

`The following differential 1-forms have been defined and protected:`

 

[_DG([["form", BlackHole, 1], [[[1], 1]]]), _DG([["form", BlackHole, 1], [[[2], 1]]]), _DG([["form", BlackHole, 1], [[[3], 1]]]), _DG([["form", BlackHole, 1], [[[4], 1]]])]

(1)
BlackHole > 

g := evalDG((-1+z)*`&t`(dT, dT)+`&t`(dT, dR)+`&t`(dR, dT)+rho2*`&t`(dTheta, dTheta)-z*a*sin(Theta)^2*(`&t`(dPhi, dT)+`&t`(dT, dPhi))-a*sin(Theta)^2*(`&t`(dR, dPhi)+`&t`(dPhi, dR))+Sigma2*sin(Theta)^2*`&t`(dPhi, dPhi)/rho2)

BlackHole > 

ON := evalDG(DGGramSchmidt([D_T, D_R, D_Theta, D_Phi], g, signature = [-1, 1, 1, 1]))

[_DG([["vector", BlackHole, []], [[[1], 1/(-(-a^2*cos(Theta)^2+2*M*R-R^2)/(R^2+a^2*cos(Theta)^2))^(1/2)]]]), _DG([["vector", BlackHole, []], [[[1], -(R^2+a^2*cos(Theta)^2)/((-(R^2+a^2*cos(Theta)^2)/(-a^2*cos(Theta)^2+2*M*R-R^2))^(1/2)*(-a^2*cos(Theta)^2+2*M*R-R^2))], [[2], 1/(-(R^2+a^2*cos(Theta)^2)/(-a^2*cos(Theta)^2+2*M*R-R^2))^(1/2)]]]), _DG([["vector", BlackHole, []], [[[3], 1/(R^2+a^2*cos(Theta)^2)^(1/2)]]]), _DG([["vector", BlackHole, []], [[[1], a*sin(Theta)^2/((R^2+a^2*cos(Theta)^2)*sin(Theta)^2)^(1/2)], [[2], a*sin(Theta)^2/((R^2+a^2*cos(Theta)^2)*sin(Theta)^2)^(1/2)], [[4], 1/((R^2+a^2*cos(Theta)^2)*sin(Theta)^2)^(1/2)]]])]

(2)
BlackHole > 

Oneform := RaiseLowerIndices(g, ON[1], [1])

_DG([["tensor", BlackHole, [["cov_bas"], []]], [[[1], (-a^2*cos(Theta)^2+2*M*R-R^2)/((R^2+a^2*cos(Theta)^2)*(-(-a^2*cos(Theta)^2+2*M*R-R^2)/(R^2+a^2*cos(Theta)^2))^(1/2))], [[2], 1/(-(-a^2*cos(Theta)^2+2*M*R-R^2)/(R^2+a^2*cos(Theta)^2))^(1/2)], [[4], -2*M*R*a*sin(Theta)^2/((R^2+a^2*cos(Theta)^2)*(-(-a^2*cos(Theta)^2+2*M*R-R^2)/(R^2+a^2*cos(Theta)^2))^(1/2))]]])

(3)
BlackHole > 

ExteriorDerivative(Oneform)

Error, (in DifferentialGeometry:-ExteriorDerivative) expected 1st argument to be a differential form. Received: _DG([["tensor", BlackHole, [["cov_bas"], []]], [`...`]])

 
BlackHole > 

``

Download teste.mw

  1. I use both Maple and Matlab
  2. I also install (a stripped down version of) Maple as the "symbolic toolbox" for Matlab using the executable MapleToolbox2022.0WindowsX64Installer.exe, which lives in C:\Program Files\Maple 2022. This gives me acces to (some) symbolic computation capability from within Matlab.
  3. This installation process has been working for as long as I remember, certainly more than 10 years
  4. With Maple 2022 and Matlab R2022a, this installation process ran with no problems and I can perform symbolic computation within Matlab
  5. However, although the Matlab help lists the Maple toolbox as supplemental software (as in all previous releases), I can no longer acces help for Maple from within Matlab - I just get a "Page not found" message
  6. The relevant Maple "help" is at the same place within the Matlab folder structure which is C:\Program Files\MATLAB\R2022a\toolbox\maple\html
  7. I have just spoken to support at Matlab and they claim tha this must be a Maple (or Maple toolbox installer issue) - so nothing to do with them!
  8. Has anyone else had a similar problem andd found a workaround?

Hello,

Im a tax student and tring to figure out Maple. I plotted the following graph with the code:

implicitplot([Vth = Vps, V1 = 25000, V1 = 50000, V1 = 75000, V1 = 100000], E = 0 .. 1000000, T = 0 .. 15, color = [black], labels = ["E in (EUR)", "T (in Jahren)"], labelfont = [times, bold, 12], view = [0 .. 1000000, 0 .. 15])

I would like to color the intermediate areas and attach a legend. A colleague has plotted this for me, but unfortunately has not provided me with the source code and has now lost the file. Can someone help me to re-plot the last shown chart?

Thanks so so much in advance!! Best regards Rebekka

Hello,

Im a tax student trying to use Maple for my studies. I plotted two surfaces in a 3D coordinate system, the surfaces intersect = indifference area.

The current formula is like this:

plot3d([Vth/E, Vps/E], E = 0 .. 1000000, T = 0 .. 15, labels = ["E", "T", ""], color = [gray, white], labels = ["E (in EUR)", "T (in Jahren)", ""], labelfont = [times, bold, 12])
It looks like this:

I would like to draw in the same graph, the indifference area (Vth/E = Vth/E), it looks like this:


A colleague has plotted this for me, but unfortunately has not provided me with the source code and has now lost the file. Can someone help me to re-plot the last shown chart?


Thanks a lot in advance!!

Rebekka

Why is the graphics quality of text so much worse in Maple than in other software?

On my screen it becomes barely readable, while Word or pdf are much better.

Same screen, same font (Arial, 11) and zoom factor (100%).

hello 

i have a loop the evaulated and prints some variables, is there a way to clear the printing between each iteration?

example : 

for i form 1 to 100 do

for j from 1 to 100 do 

x:= 5*i*j:
if j mod 10 =0 then print(j/100): fi 

od: 
## clear the printing here ##
if i mod 10 =0 then print(i/100): fi 

od:

thank you in advance 

Hello Guys

Please, sould somebody tell me if my result right or I have do something wrong with maple? THX a lot. 

Question was: y' = 1+y^2/x*y

Dgl_1 := diff(y(x), x) = (1 + y(x)^2)/(x*y(x)); result -> Dgl_1 := diff(y(x), x) = (1 + y(x)^2)/(x*y(x))

P := dsolve(Dgl_1, y(x)); result -> P := y(x) = sqrt(_C1*x^2 - 1), y(x) = -sqrt(_C1*x^2 - 1)

THX a lot 

Hello,

I have viewed on youtube the video "A Swift Introduction to Geometric Algebra" and i would like to start on the same subject with Maple but i don't even know to start !!

Do you have an idea how to start doing simple things like the "geometric product", operations on bivectors, trivectors....

Thanks

ps:  link to the video

https://www.youtube.com/watch?v=60z_hpEAtD8&ab_channel=sudgylacmoe

Dear maple user,

I have codes for Differential equations while applying one do and end loop i am able to plot the graph of G(x) while same problem with other way of applying do and end loop i am unable to plot. whats wrong with do and end loop. These are codes available in maple primes . while combining i am unable to plot .

any one resolve it.

Thanks in advance . 

 

restart:
with(DETools):
with(plots):
with(IntegrationTools):
de0 := {
    (1-p)*(diff(f(x),x,x,x))+p*(diff(f(x),x,x,x)+(1/2)*f(x)*(diff(f(x),x,x))),
    (1-p)*(diff(g(x),x$2))/Pr+p*((diff(g(x),x$2))/Pr+(1/2)*f(x)*(diff(g(x),x)))}:

ibvc0 := {f(0),(D(f))(0),(D(f))(5)-1,g(0)-1,g(5)}:
n:=2:

F := unapply( add(b[k](x)*p^k,k=0..n), x ):
G := unapply( add(c[k](x)*p^k,k=0..n), x ):

de := map( series, eval( de0, {f=F,g=G} ), p=0, n+1 ):

for k from 0 to n do

    if k = 0 then
        ibvc := expand( eval[recurse]( ibvc0, {f=F,g=G,p=0} ) ):
    else
        ibvc := { b[k](0), D(b[k])(0), (D@@2)(b[k])(0), c[k](0), D(c[k])(0) }:
    end if:

    sys := simplify( map( coeff, de, p, k ) ) union ibvc:
    soln := dsolve( sys ):
    
    b[k] := unapply( eval( b[k](x), soln ), x ):
    c[k] := unapply( eval( c[k](x), soln ), x ): 

end do:

'F(x)' = F(x)+O(p^(n+1)):
'G(x)' = G(x)+O(p^(n+1)):

Pr:=1:
plot(eval(G(x), p = 1), x = 0 .. 5, color = blue):
###### Same problem with other  way of do and and end loop unable to plot with G(x)
restart:
with(DETools):
with(plots):
with(IntegrationTools):
Pr:=1:
de1 := (1-p)*(diff(f(x), `$`(x, 3)))+p*(diff(f(x), `$`(x, 3))+(1/2)*f(x)*(diff(f(x), `$`(x, 2))));
de2 := (1-p)*(diff(g(x), `$`(x, 2)))/Pr+p*((diff(g(x), `$`(x, 2)))/Pr+(1/2)*f(x)*(diff(g(x), x)));
ibvc := f(0), (D(f))(0), (D(f))(5)-1, g(0)-1, g(5); n := 2; F := unapply(add(b[k](x)*p^k, k = 0 .. n), x); G := unapply(add(c[k](x)*p^k, k = 0 .. n), x);
DE1 := series(eval(de1, f = F), p = 0, n+1);
DE2 := series(eval(de2, g = G), p = 0, n+1);
CO := map(coeffs, eval([ibvc], f = F), p); CT := map(coeffs, eval([ibvc], g = G), p);

for k from 0 to n do IBVC1 := select(has, C*T, c[k]); slv := dsolve({coeff(DE2, p, k), op(IBVC1)}); c[k] := unapply(rhs(slv), x) end do;
G(x) = G(x)+O(p^(n+1));
plot(eval(G(x), p = 1), x = 0 .. 5);
 

Hi, Maple users 

I hope you are doing well.
Here I solved one of the ode problems by dsolve.
But I am getting  "Error, invalid subscript selector" error.
Kindly do the needful to find a solution.
Thank you.

JVB.mw

I want to explore multivariable function approximations using truncated Taylor series.

Mathematically, for a function f(x,y) and using operator notation for the partial derivatives, where e.g. Dx2 f(x,y) denotes the second partial derivative of f wrt evaluated at (x,y), we can write the N'th order truncated Taylor series for f around (x0,y0) as

I want to make a Maple-function for this expression, and try

P := (x,y,x0,y0,N) -> sum(1/factorial(n)*sum(binomial(n,k)*
D[1$(n-k), 2$k](f)(x0,y0)*(x-x0)^(n-k)*(y-y0)^k, k=0..n), n=0..N):

where f(x,y) is a previosly defined Maple-function.

My P function fails, and the reason why it fails is related to the "D" operator in the "sum".

Please take a look at the following code-snippet:

Output (9) is as expected, but output (8) is not !!
I would expect output (8) to be equal to the sum of output (9), i.e. to be equal to (-1/2).

Please illuminate why I don't get the sum of the sequence (9) as my output (8).

Hellow, 

I am unable to combine the graphs. I have a plot structure as

P1:=plots[odeplot](dsol, [x, F(x)], 0 .. 5, color = red);

P2:=plot(eval(F(x), p = 1), x = 0 .. 5, color = blue);

I want to combine two structure and display in same plot

display (P1,P2);

 thank in advance