Hello all,

Suppose I have a vector valued function f (dimensions of vectors is 2). I can use fieldplot to show me the function's behaviour over some window.

I'd like to do the same thing, but I want to compact the space down to the unit circle. Basically, given a vector <x,y>, I'd like to "fieldplot" f(<x,y>) but with each arrow f(<x,y>) appearing at <x,y>/(1 + Norm(<x,y>,2)) instead of <x,y>.

Is this possible?

Hi! I'm trying to use MapleSim 7 to simulate some very simple physical situations, however after great many hours spent at this, I'm still unable to convince MapleSim to load and run even the simplest Modelica models, like:

model Main
  Modelica.Mechanics.MultiBody.Parts.Body o(r_CM = zeros(3));
  inner .Modelica.Mechanics.MultiBody.World world;
equation
  o.frame_b.f = {0,-9.8,0};
end Main;

It will report that o and world are "unknowns" and apparently does not recongize Modelica.Mechanics.MultiBody.Parts.Body nor Modelica.Mechanics.MultiBody.World. Do I need to do some extra steps to import extra libraries or enable some non-default components?  I went through various YouTube and other tutorials and didn't find a mention of anything.

When I look at some examples, often they refer to things like Maplesoft.Multibody.World - but these are proprietary Maple packages, and I need my code to use standard Modelica. Does this mean that MapleSim cannot run generic Modelica code like this?

I also tried running e.g. https://github.com/xogeny/HarmonicMotion and some other examples, with absolutely no success either. I'm quite confused because MapleSim has a lot of advertising about Modelica support... :-(

Hello. I am engaged in independent study of tensor calculus (in the annex to the theory of elasticity) and package Maple. Currently engaged in the action of a solution of the normal point force on elastic half-space (Boussinesq problem, for example, see http://solidmechanics.org/Text/Chapter5_4/Chapter5_4.php#Sect5_4_4). The point is this: you need to create a vector displacement field U, differentiate and create a strain tensor, and then using Hooke's law to obtain the stress tensor. Actually only started to understand and immediately raised the question. Creating vector displacement field using the VectorField package VectorCalculus or any team or package DifferentialGeometry Physic? How then create a tensor with components equal to the partial derivatives of the displacement vector? My attempts Boussinesq_problem.mw. Thanks for your help.

I need to write a procedure that does the following :

Write a procedure quadsum whose input is an integer n and whose output is a list of pairs of solutions [x,y] to the above formula.

Your procedure should implement the following algorithm.

1 Initialization
Set
"mylist = []."

Start at
x = 0
and
y = 0.

2 Phase A
Increment both
x
and
y
until
"x^2+y^2 >=n."

Phase B
Repeat the following until
x^2>n

If you are above the circle
x^2 + y^2 = n
then go down in unit steps until you are on or below the circle.

If you are on the circle, add the point to the list
"mylist. "

If you are on or below the circle
x^2 + y^2 = n
then go one step to the right. My procedure is as follows: but it runs into an infinite loop(most probably because of the while loop defined inside the while loop). What am I doing incorrectly?

I have atta

Has there been any progress with new commands for Maple 13 that allow one to auto-resize the plotting grid?

I am generating fractals with Maple 13 and resizing the plot output grid manually is not an option because it distorts it. Neither is the option to resize it once and recalculate, because the final grid contains many points.

Any pre-processing or massaging code prior to executing the main code is very welcome (if it can be done).

Many thanks,

Yiannis

Hello together,

After doing some Maple work i got this Equation of Motion:

I'm not sure how I am able to solve this differential equation.

I am able to do it by Seperation of the variables by hand, but Maple should be able too?

Thanks for the help, everything is appreciated!

When I plot someting in Maple17, it appears in a small square window that's horizontally centered.  I want to be able to create plots that appear larger.  There's plently of space on the screen for plots to be much larger.

Yes, I know I can grab the corner of a plot and drag it to make it bigger.  That's not what I want (that takes time, and it's tricky to maintain the aspect ratio).  I want the plot to appear large when I execute the plotting command.

I've searched for answers both on Google and mapleprimes, and come up empty.

If I have the following system of first order diff eq's:

x'(t)=2x(t)+3y(t)

y(t)=-3x(t)-2y(t)

then can I consider the coefficient matrix A=<<2,-3>,<3,-2>> and compute the eigenvalues of A and infer as follows:

if the eigenvalues are of the same sign- eq point is a node

if they are of opposite signs- eq point is a saddle

if they are pure imaginary- eq point is a center

if they are complex conjugates- eq. point is a spiral

I've been given these conditions but my text says for a linear system of the form x'=Ax, the eigenvalues of A can be used to identify the nature of the eq. point. I am confused as to whether this applies to the given system as well; I have obtained 5 different trajectories and drawn the phase diagram for the system

I have the following :

with(powseries):
difeq:=diff(y(x),x,x)+x*y=0;
icval:=y(0)=1,D(y)(0)=0;
pow_soln:=powsolve({difeq,icval});
tpsform(pow_soln,x,30);
pow_soln(_k);

for which the  transformed power series

is : 1 -(1/6)y*(x^3)

and pow_soln(_k) returns 0. What does this mean?

What is the best way to solve for the simple equation X^2+y^2=1[m]^2 symbolically for either x or y? I actually have a huge list of equations and want to solve the group but my problem boils down to the issue here where I get two possible solutions though using the assumption one is clearly negative and the assumption used should exclude negative results (see attempt below). Also solve doesn't seem to work with units either...  any ideas? Can I give the variables units in a meaningful way?

--------------------------------------------------------------------------------------------------------------------------

restart;

with(RealDomain);
f := x^2+y^2 = 1;

                            x^2+y^2 = 1

assume(y > 0)

a := y > 0

y1 = solve(f, y, useassumptions = true)

                          y1 = (sqrt(-x^2+1), -sqrt(-x^2+1))

y2 = solve({a, f}, y)

                          y2 = ({y = sqrt(-x^2+1)}, {y = -sqrt(-x^2+1)})

-------------------------------------------------------------------------------------------

Why is y = -sqrt(-x^2+1) a solution?

Also, how do I use units when trying to solve 

-------------------------------------------------------------------------------------------

restart;
f := x^2+y^2 = Unit('m')^2;
                           x^2+y^2 = Unit('m')^2

assume(x > 0);
assume(y > 0);
d = solve(f, y, useassumptions = true);

Error, (in Units:-Standard:-+) the units `m^2` and `1` have incompatible dimensions

---------------------------------------------------------------------------------------------

THANKS!

My assignment is to plot 3 graphs when u0=65.70 and 95 and I thought I did my code properly but now I am getting weird errors

a0:=80;
a1:=-5;
b1:=-5*(3)^0.5;
w:=Pi/12;
k:=0.2;
u0:=65;

t=0:0.001:100;
c0=u0-a0-(k^2*a1-k*w*b1)/(k^2+w^2);
c1=(k^2*a1-k*w*b1)/(k^2+w^2);
d1=(k*w*a1+k^2*b1)/(k^2+w^2);
u=a0+c0*exp(-k*t)+c1*cos(w*t)+d1*sin(w*t);
plot(t,u,'r');

I am getting an error here that says Error, (in plot) unexpected options: [65., r] and I don't know how to fix this


legend('u(0)=65');

hold on;
u0=70;
c0=u0-a0-(k^2*a1-k*w*b1)/(k^2+w^2);
c1=(k^2*a1-k*w*b1)/(k^2+w^2);
d1=(k*w*a1+k^2*b1)/(k^2+w^2);
u=a0+c0*exp(-k*t)+c1*cos(w*t)+d1*sin(w*t);
plot(t,u,'-');

I am also getting an error with the '-' portion of my plot "Error, invalid uneval"

legend('u(0)=70');

hold on;
u0=95;
c0=u0-a0-(k^2*a1-k*w*b1)/(k^2+w^2);
c1=(k^2*a1-k*w*b1)/(k^2+w^2);
d1=(k*w*a1+k^2*b1)/(k^2+w^2);
u=a0+c0*exp(-k*t)+c1*cos(w*t)+d1*sin(w*t);
plot(t,u,'g');

I am getting an error yet again with my plot and this time it is "Warning, expecting only range variable u in expression t to be plotted but found name t"


legend('u(0)=90');

I am new to maple, having recently made the switch from mathCAD, and I am having problems getting the basics to do what I think they ought to be doing.

I am trying to get maple to go step by step through a derivation of a formula. In one line I define a variable

U4 := expression

In the next line I will call the same variable and take the derivative of it. Sometimes it works and sometimes it evaluates to zero when it should not. I can't seem to pin down a pattern of when it does and does not work. I will change something that is not working, and then change it back, and it will work. Am i assigning my variables inconsistently? 

I took a screencapture of the worksheet in question. Thanks in advance for the help.

****** My question *****

for k from 0 to n do    # n is any integer.

func := f(x):             # func is any funciton of x.

D := diff(func, x$k);   # The maple don't allow to uses k but I want to diff k-th order in each k-loop.

end do;                    # How to diff func for k-th times in each k-loop.

Hello guys,

I am stuck with the following code. I cannot get a solution. Mapple doesn't even run. Please help, I am in urgent need on help!!!

Compared to Maple on Windows, how do ppl like Maple on Macs ?

Any comments ??

Thanks, cheers !

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