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?

Hello,

I am having problems with Maple. I am new to the software and I am looking to use it for tensors. I am working with the Alcubierre metric, for more details, click the images below.

https://i.imgur.com/OvBywO6.png

https://i.imgur.com/2D9Y73x.png

These images should provide more clarity with the metric. My problem is that in Maple, I have successfully entered the metric, however whenever I use for example the Christoffel command, it states that all the Christoffel symbols are equal to zero.

https://i.imgur.com/VRDQM8d.png

I believe the reason why this is happening is because I have not defined the functions properly. I should be getting an answer like the example in the last picture below.

https://i.imgur.com/tn8HpIE.png

Would anyone be able to assist me in this? I would appreciate it greatly.

Many thanks.

Each term of the following sequence is derived using the sum of all preceding terms following a simple algorithm. I have tried to code it but without success (keep getting error message "too many levels of recursion"). 

Definition is as follows:

a(0)=0, a(1)=1;  for n>=1,

a(n+2) = n + Sum{k=1..n+1} a(k). 
 

it starts: 0,1,2,5,11,23,47,95,191,767,1536,3071,6143...

(Looks like every prime term is of the form 3*2^m-1). 

Cann anyone suggest a solution?

Thanks,

David.

Hi,

While computing a simple sequence of numbers, I remarked a small difference between the result obtained with $ and with seq.

Digits:=20:
u:=proc(n) evalf(((n+1)/n)^(n+1)) end proc:
a:=[u(n)$n=1..10]:
b:=[seq(u(n),n=1..10)]:
a-b;

The result is:

[0., 0., -4.*10^(-19), 0., 0., 6.*10^(-19), -9.*10^(-19), 0., -3.*10^(-19), 0.]

I have no idea why there are nonzero values in the output. Does anyone have an explanation?

It seems I get the correct values if I quote the expression before $:

a:=['u(n)'$n=1..10]:

However, it's not clear to me why this makes a difference in evalf.

As the title says， I'd like to  divide Non-isomorphism  graphs of order 7   into 6 parts according  diameter of graph.

I write following codes:

But I think  conditional statements  if.. elif are used to many  in  above maple  codes,  it is not concise.  

How to write better?

Projection will not work with orientation. 

plot3d(x*y, x = 0 .. 10, y = 0 .. 10, projection = 0.2)
                                                        

plot3d(x*y, x = 0 .. 10, y = 0 .. 10, projection = 0.2, orientation = [55, 75, 0])
                                                

After setting:

Digits:=20;

result of:

evalhf(9.3653976306373904636884810627704*10^(-315));

is:

-9.0813464423699167205*10^(-315)

This looks nonsesnse. What is going on?

how to show which region of the plan belongs to the argument points between 0 and Pi/2 and the module points between 0 and 2 ?

Does anyone know how to open .mm file in Maple, as well as using the program or function in .mm file in Maple? Many thanks.