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]);

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

?Student[LinearAlegbra]

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?

Why 

evalf(evalf(''Pi''))

Produces 

But

evalf(''Pi''):
evalf(%)

Produces

      3.141592654

Could some Maple expert please explain this strange behavior of int? Using Maple 2020 on windows 10

Same integrand. But in one case exp(arcsin(x)) and in another exp(1)^arcsin(x). Why one worked and not the other?

Here is the code

restart;
integrand1 := (x^3*exp(arcsin(x)))/sqrt(1 - x^2);
integrand2 := (x^3*exp(1)^arcsin(x))/sqrt(1 - x^2);
simplify(integrand1-integrand2);
int(integrand1,x);
int(integrand2,x)

Download bug.mw

Hi - High school teacher 

I'm using the with(Physics): Setup(mathematicalnotation=true):with(Physics[Vector]): libraries which gives elegant answers to some of the questions of elementary vector algebra. 

But I become stuck when I try to simplify a simple expression like

Equa[01]:=AC_ = AB_ + BC_:Equa[01];                            #AC_ = AB_ + BC_
Equa[02]:={AB_=2*DB_,BC_=2*BE_}:Equa[02];
Equa[03]:=subs(Equa[02],Equa[01]):Equa[03];                #AC_ = 2*DB_ + 2*BE_
simplify(Equa[03]);                                                              #also try combine

which gives

AC_ = 2*DB_ + 2*BE_

rather than what I was hoping for

AC_ = 2*DE_

I have define a type and build a clumsy addition procedure - with no hope of overloading '+'

But I am sure that their exist a better solution - which if possible should remain within the Physics[Vector] library. It is hard enough to convince high school student to use maple. Maybe adding rule in the setep... I just don't have the required time to look around.

Any help would be appreciated.

Thank

Jean-Marc Roy

Note:

Hi, I am trying to add some useful inverse Laplace transforms to Maple's integral tables. I am frustrated that these transforms will only be recognized  if they are entered in exactly the same format. For example, if I type:

restart;

with(inttrans):

addtable(invlaplace, 1/(s^y*sqrt(a + s^x)), Sum(a^n*sqrt(Pi)*t^(-1 + (1/2 + n)*x + y)/(GAMMA(1/2 - n)*GAMMA(1 + n)*GAMMA(1/2*x + n*x + y)), n = 0 .. infinity), s, t, {a, x, y}, y::Range(-infinity, infinity), x::Range(-infinity, infinity), a::Range(-infinity, infinity));

savetable(invlaplace, `InvlaplaceTable.m`):

Then:

restart;

with(inttrans):

read `InvlaplaceTable.m`:

invlaplace(1/(s^y*sqrt(a + s^x)), s, t);#Ok works for general

invlaplace(1/(s^3*sqrt(a + s^x)), s, t);# Dosen't WORK ?# For y = 3.

invlaplace(1/(s^3*sqrt(s^3 + a)), s, t);# Dosen't WORK ?# For y = 3. and x = 3

value(eval(invlaplace(1/(s^y*sqrt(a + s^x)), s, t), [y = 3, x = 3]))#Workaround !!!

Thanks.