Maple 2020 Questions and Posts

These are Posts and Questions associated with the product, Maple 2020

Hi, 

I work for the University of Dundee as a packager for the staff and student desktops.

We have a licence for 2020 applied to our licance server, I only require the software.

Is your free version the full package that once it sees the licence server will unlock all the features do I need to download a specific version from yourselves,

Best regards

Colin 

Hello everyone! I'm pretty new to Maple and struggling with some basics.

 

I want to use a for-loop to print out the square numbers from 11 to 20. And the outputs should be presented within a list.

This is what I have so far:

|> for i from 11 to 20 do print(i^2) od;


                              121

                              144

                              169

                              196

                              225

                              256

                              289

                              324

                              361

                              400

But I don't know how I can put all these results in a list, so that in the end it looks like this:

L: = [121,144,169,196,225,256,289,324,361,400]

 

I'm grateful for every answer :)

 

 

With Maple 2020, I have been experiencing some odd behavior of simple 2D plots. For example, I plotted two functions on the same graph, and the default view did not contain the full upper or lower limits of both functions. (Sorry, I chose to move on and so I am unable to reproduce this outcome – but it has happened more than once.)  

Now I am experiencing another limited view of a plot, this time a single function. In creating a simple example of the SIR model, I have dsolve output a list of procedures so that I can plot them as functions. But when I plot one of the functions, it does not plot the entire function from the lower to the upper limit. Am I alone in experiencing this outcome? Is there something I am doing wrong that is causing this behavior?

 

restart; plots:-setoptions(size = [300, 300])

s_eq := diff(s(t), t) = -ir*i(t)*s(t); i_eq := diff(i(t), t) = ir*i(t)*s(t)-rr*i(t); d_eq := diff(d(t), t) = dr*i(t); ics := s(0) = s0, i(0) = i0, d(0) = 0

"i0:=1.E3:    P0:=3.E8:    drate:=0.02:     s0:=0.6*P0:    ir:=(0.1)/(s0):   rr:=1/(30.):  dr:=rr*drate:   "

sol := dsolve({d_eq, i_eq, ics, s_eq}, numeric); tf := 120; plots:-odeplot(sol, [t, d(t)], 0 .. tf)

 

sol := dsolve({d_eq, i_eq, ics, s_eq}, numeric, output = listprocedure); i := eval(i(t), sol); s := eval(s(t), sol); d := eval(d(t), sol)

tf; plot(d(t), t = 0 .. tf)

120

 

 

plot(d(t), t = 0 .. tf, view = [0 .. 150, 0 .. 40000])

 

``


 

Download plot_view_problem.mw

When I use something like plots[display](Array([p1,p2]));  And the plots p1,p2 have been resized before to be small, there is lots of wasted empty space in the final result. I have to manually adjust the size of each Array entry with the mouse to make the fit better. But this solution is not practical. 

Is there an option to do this automatically? Here is an example

restart;

p1:=plot(sin(x), x=-Pi..Pi, size=[300,300]):
p2:=plot(cos(x), x=-Pi..Pi, size=[300,300]):
plots[display](Array([p1,p2]));   #one option
plots[display](Vector[row]([p1,p2])); #another option

Manually, using the mouse, I can, after some adjustments and trrial and errors, get the final result such that the wasted space is removed.

I am asking, becuase if I want to save/export the above final plot as PDF to include in a Latex document, it will look bad with that wasted space there.

How to do this adjustment using code?

In Mathematica for example, this is done using Grid and the Spacing option. I could not find something similar in Maple but I could have overlooked it.

Maple's plot3d makes nice plots, but it is not quite polished enough I feel.

When I compared the same plot with what I get with Mathematica, I found these 3 issues shown below. I am not too good in Maple, so I am not able to see how to improve on this any more.

 

 

The Maple code is

restart;
f:=-x^4-2*y^4+14*x^2*y^2/5:
plot3d(f, x=-5..5,y=-5..5,
   axes     = boxed,
   axesfont = [Times,default,10],
   axis[1]  = [tickmarks=[3,subticks=5]],
   axis[2]  = [tickmarks=[3,subticks=5]],
   axis[3]  = [tickmarks=[3,subticks=5]],
   labeldirections = [horizontal, horizontal, horizontal],	
   labels   = ['x', 'y', 'z'],
   scaling  = unconstrained) 

Compare to Mathematica's output

 

f = -x^4 + (14*x^2*y^2)/5 - 2*y^4; 
Plot3D[f, {x, -5, 5}, {y, -5, 5}, 
 AxesLabel -> {"x", "y", "z"}, 
 PlotRange -> All, 
 BoxRatios -> {1, 1, 1}, ImageSize -> 400]

Another major limitation in Maple's plot3d, is that it does not support `BoxRatios` like option. I asked about this years ago and got help on it, but nothing very satisfactory to use in geneal.

https://www.mapleprimes.com/questions/217092-How-To-Change-box-Ratio-Or-3D-Aspect

I hope Maplesoft can improve on this in next version.

Any suggestion how to improve the above 3 issues for now? The ticks issues for me seems the most annoying, becuase they keep moving around as I rotate the 3d plot.

 

Maple 2020 on windows 10

This app shows the modeling and simulation of DNA carried out entirely in Maple. The mathematical model is inserted through the combination of trigonometric functions. It shows the graphs of the curvature vs time for its interpretation. Made for engineering and health science students.

MV_AC_R3_UNI_2020.mw

Lenin Araujo Castillo

Ambassador of Maple

 

 

Dear Maple users

I have had problems with Maple 2020. I am using Windows 10, by the way, and have several versions of Maple installed: 2019, 2018 and even 2017. Now however I am unable to open a Maple file from Windows Explorer either by double-clicking or by right-clicking and choosing "Open with" Maple 2020. Nothing happens when I try so! It works properly when I choose older versions of Maple. I have about the same problems on another computer, an Ultrabook. It is really a pain having to open Maple 2020 and then having to browse all the way down a file path ... 

NB! I have tried reinstalling, but it didn't help!

I hope someone have an idea how to solve this issue. Can it be solved in the Windows Registry?

Regards,

Erik

With the new features added to the Student[LinearAlgebra] package I wanted to go over some of the basics on how someone can do Linear Algebra in Maple without require them to do any programming.  I was recently asked about this and thought that the information may be useful to others.
 

This post will be focussed towards new Maple users. I hope that this will be helpful to students using Maple for the first time and professors who want their students to use Maple without needing to spend time learning the language.
 

In addition to the following post you can find a detailed video on using Maple to do Linear Algebra without programming here. You can also find some of the tools that are new to Maple 2020 for Linear Algebra here.

The biggest tools you'll be using are the Matrix palette on the left of Maple, and the Context Panel on the right of Maple.

First you should load the Student[LinearAlgebra] package by entering:

with(Student[LinearAlgebra]);

at the beginning of your document. If you end it with a colon rather than a semi colon it won't display the commands in the package.

Use the Matrix Palette on the left to input Matrices:

 


Once you have a Matrix you can use the context panel on the right to apply a variety of operations to it:

 


The Student Linear Algebra Menu will give you many linear algebra commands.

 


You can also access Maple's Tutors from the Tools Menu

Tools > Tutors > Linear Algebra



If you're interested in using the commands for Student[LinearAlegbra] in Maple you can view the help pages here or by entering:

?Student[LinearAlegbra]

into Maple.

I hope that this helps you get started using Maple for Linear Algebra.

When I tried these ODE's in Maple 2019, and Maple 2018, they are worked (i.e. gave solutions). Now these ODE's either hang in 2020 or return unsolved. What could have caused this? On Maple 2020, under windows 10:

restart;
ode:=(x^2-1)*diff(y(x),x)^2-y(x)^2+1=0:
dsolve(ode); #hangs

restart;
ode:=(2*x^2+1)*diff(y(x),x)^2+(y(x)^2+2*x*y(x)+x^2+2)*diff(y(x),x)+2*y(x)^2+1=0:
dsolve(ode); # return unsolved

restart;
ode:=x*y(x)^2*diff(y(x),x)^3-y(x)^3*diff(y(x),x)^2+x*(x^2+1)*diff(y(x),x)-x^2*y(x):
dsolve(ode); # return unsolved

restart;
ode:=(diff(y(x),x) = (-y(x)^2+4*a*x)^3/(-y(x)^2+4*a*x-1)/y(x)):
dsolve(ode); #hangs

I noticed that in Maple 2019.2 this problem is also there. But not in Maple 2019.  So something changed from after Maple 2019.

Here is worksheet on Maple 2018 that shows these worked there. But no longer work on Maple 2020. There might be more like these but these the ones I found so far.




issue.mw

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?

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

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.

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.

After setting:

Digits:=20;

result of:

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

is:

-9.0813464423699167205*10^(-315)

 

This looks nonsesnse. What is going on?

 

 

 

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