Hi folks!

Is there any way to make this kind of derivative?

If necessary, I can provide the original file here.

Thanks in advance for any help!

If I understand how to use vectors in Maple, I need to give the number of elements.  Is this correct?  I am working with vectors that I do not know the number of elements.  I can use a large number that will be greater than the required number of elements, but this does not seem to be a good solution.  The number of elements is 2000 for about 10 different vectors.  What is the best method to set up the victors for this application?

Can anyone help me to frame the equations in Fractional Reduced Differential Transform Method 

system of nonlinear ordinary differential equations
ds/ dt = b−γ s(t)− (δ s(t)(i(t) + βa(t)) /N − ε s(t) m(t) 
de/ dt = δ (s(t)(i(t) + βa(t))/ N + ε s(t) m(t) − (1−ϑ) θ e(t) − ϑ α e(t) − γ e(t) 
di/ dt = (1−ϑ) θ e(t) − (ρ + γ) i(t)
da/ dt = ϑ α e(t) − (σ + γ) a(t)
dr /dt = ρ i(t) + σ a(t) − γ r(t)
dm /dt = τ i(t) + κ a(t) − ω m(t) 

Good day to all.

I have a function, z(x,y), that I am interested in exploring. The contour plot returns the z-contours on the x-y grid (see attached).

Can anyone suggest a way in which I can now assign z to the vertical axis (instead of y), x to the horizontal axis, and plot the contours for various y-values?

Thanks in advance.

Contour_Plot_MaplePrimes.mw

How can I  get the "phase portrait including vector fields" and several trajectories of the following dynamical system in the polar coordinates (Note that the system is also in polar coordinate)??

(-(2*I)*c1*eta+c1*sqrt(-e0^2-4*eta^2))/e0 = c2, ((2*I)*c2*eta+c2*sqrt(-e0^2-4*eta^2))/e0 = -c1

How can we remove c1 from the expression of c2 and similarly c2 from c1?

Hi

I try to visualize and animate the hollow volume between two functions, but I do not have an optimal rendering

Ideas? Thanks

,Q1.mw

The worksheet below displays dual cones inside the unit sphere, but the Gauss-Bonnet formula (area of upper cone's spherical cap plus length of dual cone's intersection with unit sphere) does not equal 2*Pi.

Please find my error.

Dual_cones.mw

In Maple 2020, I clicked on "Math Apps" and then clicked on "Algebra & Geometry", followed by "Boy's Surface".

It is a set of 3 parametric equations in terms of {u,v}. I would like to eliminate u and v and turn this into a single "error" function in terms of (x,y,z) such that anywhere this function is zero, the original set of equations are satisfied for some value of {u,v}. (Ideally, the values of u and v could be determined as well, but that would be a bonus.)

I tried this:

alpha = 1;
u in [-Pi/2, Pi/2];
v in [0, Pi];
eq1 := x(u, v) = (sqrt(2)*cos(v)^2*cos(2*u) + cos(u)*sin(2*v))/(2 - alpha*sqrt(2)*sin(3*u)*sin(2*v));
eq2 := y(u, v) = (sqrt(2)*cos(v)^2*sin(2*u) - sin(u)*sin(2*v))/(2 - alpha*sqrt(2)*sin(3*u)*sin(2*v));
eq3 := z(u, v) = 3*cos(v)^2/(2 - alpha*sqrt(2)*sin(3*u)*sin(2*v));
eliminate({eq1, eq2, eq3}, {u, v});

but got no response and no error message.

Additionally, I tried explaining that I want a function f such that f(x,y,z)=0, but again got no response and no error message:

eq4 := f(x, y, z) = 0;
solve({eq1, eq2, eq3, eq4}, f);

Any ideas what I'm doing wrong?

Thank you!

-- Glenn

Hellow everyone,

Consider the following diffrential equation:

(dA(x)/dx )^2+V(A)=0,
1- How to plot dA/dx vs A?

2- How to find the coordinate of intersection point of f(x)=e-b*exp(x)-c*(1-2*x/c)^(1/2) with df/dx? e,b,c are constants.

Hi everyone! I was writing this code for an interactive component, when I stumbled into a problem that I couldn't solve...

Here is the code.

Now this are what the names stands for:

%Pari is a math conainer in which there is a function of n that is to be used when n is even;

%Dispari is a math conainer in which there is a function of n that is to be used when n is odd;

"Risultati" is the name of a spreadsheet on which the results will be displayed;

%NIterazioni is a math conainer in which there is a posint that indicates how many times the procedure is to be iterated;

%NIniziale is a math conainer in which there is the starting number (another posint) to which on which the procedure will operate;

%E is a text area that will signal the validity of the input.

What I wanted to do was a procedure that reiterated two function on a given number a given amount of times and returned the result of every passage, however, when computing, it returns the function in n and not the final numbers. 

Here is what I mean! (Click for the link, hope Google Drive doesn't break the code when downloaded.).

I have opened the Spread package in the startup-code, and I really want to use the spreadsheet even though it is deprecated in newer versions. When you'll open, the function will be the ones of the Collatz Conjecture, however I want it to be able to iterate any function of n, which will be acquired via input, and will be to the user's choice.

I tried everything that came to my mind: using text area, assigning n outside of the preocedure, using evalf, eval, putting the return inside the if system, opening and closing a do inside "then" and one isndide "else" , changing names and everything... But I couldn't solve it. on the internet and on the MapleHelp I didn't find anything.

So can anyone tell me ( most importantly) why it doens't compute the formulas and just leaves them as input and (less important then the why, but still important and would appreciate) how can it be solved? Thanks to everyone even if you just read this, I know it is amybe a little too much.

Hello

Unfortunately I run out of ideas on how to solve the problem of searching and removing elements in a variable size list.  Below you can find an example.

parms:=[seq(seq(alpha[i,j],j=0..9),i=1..3)];
abc:=combinat:-choose(parms,3):

the condition to remove the element of the list is given by the following procedure.

conds:= proc(varCoef::list,vars::name:=alpha)
local T1,T2,res;
#
T1 := table([2=3,3=2,5=6,6=5,7=9,9=7]):
T2 := table([2=3,3=2]):
#
res:=map(u->vars[`if`(assigned(T2[op(1,u)]),T2[op(1,u)],op(1,u)),
         `if`(assigned(T1[op(2,u)]),T1[op(2,u)],op(2,u))],
    varCoef);
res:=convert(convert(res,set),list):
end proc:

Something like

member(conds(abc[1]),abc,'k')

if it is a member, the element indexed by k should be removed from abc and then the search continues using the next element in abc (that now has one less element).   Otherwise, the element is kept and the search moves to next one.  The process ends when the last element in a short version of abc is tested.

Thanks all for the help and patience.

Ed

Dear experts

I am interested to solve the following equation numerically by Maple. I would appreciate it if you let me how I can do and what the boundary conditions and initial values are needed

eq:= diff(2*diff(eta(x,y,t),t)+3*eta(x,y,t)*diff(eta(x,y,t),x)+(1/3-1/epsilon/B)*diff(eta(x,y,t),x,x,x),x)+diff(eta(x,y,t),y,y)-1/sqrt(Pi*R)*int(diff(eta(x+zeta,y,t),x,x)/sqrt(zeta),zeta=0..t/epsilon)=0;
where

1) epsilon, B and r are constant

2) 1/epsilon/B is not equal to 1/3 at all

choosing lightmodel=none and shading=none, produces a dark grey grided surface
plot3d(x*y, x = 0 .. 10, y = 0 .. 10, lightmodel = none, shading = none)

adding the style=wireframe option gives a blank plot.  Grid probably white?  Changing style to patchnogrid the surface is indeed white. However chosing both shading and style options to none regardless of the lightmodel will produce a plot that appears empty.  Is this to be expected?

However, just the style=wireframe option produces a colored grided wireframe as to expect
plot3d(x*y, x = 0 .. 10, y = 0 .. 10, lightmodel = none, style = wireframe)

Dear users

All my recent questions are removed by "mapleprimes" automatically. who knows the reason?