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.

Hello colleagues,

I would like to get a suggestion on how to utilize an existing `simplify` function or to define an operator, which allows the following simplification:

— Alexander

Hello

I need to test a huge amount of subsets and for doing that I was thinking of using combinat:-subset, since it avoids allocating memory for all subsets.  The problem with subset for my specific application is that it generates sets with all possible sizes and I just need subsets with a chosen number of elements.  Can that be done in maple?  

Many thanks

Ed

I have a plot of points in a graphical plot on the domain (x,y).  At each point xi (i=1..N) , there is a numerical value yi = S(xi) from which I plot a series of points (xi, S(xi)) in the (x,y) domain.     

Each point (xi,yi) represents a transient plot of two variables u(x,t) and v(x,t) in a plot file.  Is it possible to define a graph of the points (xi, S(xi)), such that clicking on any such point in the graph opens up a graphical file which is parameterised by (xi, S(xi))?

Would welcome help on this...

Melvin

Hi, 

when running a for do cycle the first two solutions are exact the same numbers, which is not correct. Can someone plesa help me fix this problem?

Thanks a lot.

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