In this section, we will consider several linear dynamical systems in which each mathematical model is a differential equation of second order with constant coefficients with initial conditions specifi ed in a time that we take as t = t0.

All in maple.

Vibraciones.mw

(in spanish)

Atte.

L.AraujoC.

I am trying to use maple to plot a poincare section for the following Hamiltonain:

H:=(1/8)*(p1^2+16*p2^2-4*p1*p2*cos(q1-q2))/(3+sin(q1-q2)^2) - cos(q2)-8cos(q1)

I've been using Maples built in command as follows:

poincare(H, t=-5000..5000, ics, stepsize = 0.1, iterations = 1, scene = [q2,p2]);

for a given set of initial conditions ics. My problem is however I need to restrict the plotting value to p1>0, as otherwise i seem to get two overlapping maps as seen below:



How exactly can i do this?
Thanks
Connor

This is a question I have also submitted to the technical support, I am worried that it is a bit too technical for them, however:)

I am debugging a C program which links against the OpenMaple API library (under Linux and with Maple 17 and 18). I am using valgrind memcheck, because I am experiencing strange behavior which could be due to writes beyond allocated blocks of memory.  

The first thing which jumps to my eye, are many errors of the types

Use of uninitialised value of size (4/8/16)

Invalid read of size (4/8/16)

Conditional jump or move depends on uninitialised value(s) 

The same errors are also printed when I use the examples that ship with Maple. For instance, I compile "simple.c" with

gcc  -Wl,--no-as-needed -lmaple -lmaplec -lrt -L /usr/lib -L $MAPLEDIR/bin.X86_64_LINUX -I $MAPLEDIR/extern/include -o simple simple.c

and run valgrind as

valgrind --tool=memcheck --error-limit=no --log-file=memcheck.log ./simple

memcheck.txt 

Some, but not all, of the errors occur in __intel_sse2_strcpy or __intel_sse2_strlen. Furthermore, according to valgrind there are definite memory leaks. which appear in the library. 

Practically this makes it hard for me to identify my potential own errors. I am a bit surprised to see so many warnings because I tend to fix my own programs until memcheck does not print these anymore (before I give it away at least). The question is: Can I consider these errors as safe to ignore? How would I distinguish real errors which may appear in my application?

Hello,

How can I write a code to calculate the Rieman Sum for  y=x^1/2 [0..4] using 

left hand rule and 100 subdivision.

Thank you 

Hi guys, 

       After my calculations, I got the Lagrange function having three gereralized co-ordinates namely u,v and w. Hence, according to theory it should give three equations of motion. 

      I have trouble finding equations of motion from following Lagrange function(L = T -U), Can anyone guide me with this?

      Moreover, kinetic energy and strain energy equations are in the form of double integral!! 

Hello,

i need help!!

write a procedure for the taylor series sin (x) and plot it in the range (-2pi to 2 pi)

use 20 term iterations in the taylor series approximation.

Thank you very much for your help.... 

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?

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.