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Hello!

I have to  solve following ODE set as a part of my MsC thesisr^2*Hr[r, r]+(r+(1/2)*r^3)*Hr[r]+(r^2-4)*Hr+2*R*(1-exp(-(1/4)*r^2))*Hi-(1/2)*R*r^2*exp(-(1/4)*r^2)*Sii-(1/8)*R*r^4*exp(-(1/4)*r^2) = 0

 

Hi,

Can someone please tell me why I am getting this error (in bold):

> ODE := diff(y(x), x)+3*y(x) = x^2
                                     
> ics := y(0) = 1

> dsolve({ode,ics})

Error, (in dsolve) not an ODE system with respect to the unknowns {y(0)}

How to draw slope field associated to differential equation: dy/dt = sin(ty) on Maple software?

Firstly applogies for if this question has been asked before.

I am trying to plot a simple epidemic model for where I can change the rates.

My equations are:

de1:= diff(X(t),t)=a*X(t).Y(t);

de2:=diff(Y(t),t)=a*X(t).Y(t) - b*Y(t);

where X is susceptibles and Y is infected.

I would like to be able to produce a graph with the susceptible and infected plotted. Where i can change the initial conditions of X(0) and Y(0) using sliders...

One of my friends would like to buy a book about solving multiple integrals and/or ordinary differential equations with Maple (some newer version, let's say 13 and newer).

I know about this site: http://www.maplesoft.com/books/, but can anyone recommend some book(s) which is (are) worth buying?

Hello experts in Maple,

I'm going to solve IVP numerically by this command bellow:

var:={u(t),v(t),w(t)}: 
dsys1 :=diff(u(t),t)=-(Gamma+AM*cos(q*t+phi))*u(t)+(Delta-AM*sin(q*t+phi))*v(t)+Omega*w(t), diff(v(t),t)=-(Delta+AM*sin(q*t+phi))*u(t)-(Gamma-AM*cos(q*t+phi))*v(t), diff(w(t),t)=-0.5-2*Gamma*w(t)-Omega*u(t):
dsol1 :=dsolve({dsys1,ini1},numeric,method=lsode,var, abserr=1e-9, relerr=1e-8,output=listprocedure):
dsolu:=subs(dsol1,u(t)):dsolv:=subs(dsol1,v(t)):dsolw:=subs(dsol1,w(t)):...

Hello

I am trying to do a do loop that solve ODEs with initials conditions but i am having problems asking my do loop to use what we get from first run to run the secound one.

For example:

for i from 1 to 10 do

a

b

c

end do;

so first when i =1 we get a b and c then for i=2 we want what we get from i=1 to do i=2 and so on. 

Is it possible to do such a do loop? to ask maple to save what it get from...

code efficiency...

February 22 2012 ABond 25

Dear all,

Some time ago I asked a question concerning the algorythm for numerical dsolve and related issues here.

I got a nice answer from pagan and implemented the algorythm.

However, since my system is big, the iterations take long time.

Here is the code itself:

sys1:=[TRIC[1],TRIC[2],TRIC[3],TRIC[7],TRIC[8],TRIC[9]]:
> sys2:=[TRIC[4],TRIC[5],TRIC[6],TRIC[10],TRIC[11],TRIC[12]]:
> GRAD:=subs(u=FF[1](t),a=FF[2](t),k=k(t),tau=tau(t),psi[1...

I am trying to model a multibody system using euler lagrange equation. There are 3 links in the system attached with each other by revolute joints. The first link has one end fixed with the revolute joint.

Length of links= l1,l2,l3

Angle with x axis=Theta1,Theta2,Theta3

Mass of links=m1,m2,m3

Moment of Inertia = M1,M2,M3

I am not able to find the solution of ODE system comprising of 3 ODEs which I get after solving Euler Lagrange Eq for...

Dear all,

I am stuck with my gradient projection algorythm. I asked several questions on this but nothing helped.

So, the basic problem I have is the following:

I need to make a procedure, which would take as an input some function of time, x(t),

calculate numerical solution for the ODE system

diff(y(t),t)=f(t,x(t),y(t))->y_1(t)

via dsolve/numeric

then update the value of the function x(t)=f(y_1(t)),

giving as a result x(t...

I converted an ode using the built-in "convert" tool to check some calculations I had done by hand. To my surprise, there was an inconsistency. I converted the ode using PDEtools[dchange], reproducing the steps I had followed manually, and they checked out. So my question is: is there a sign error in convert? (and therefore a bug) or are both conversions correct, and if so are there any lessons to be learned? (is it related to the equation's symmetries?)

Thanks for your comments.

Hey everyone.

I have been trying to solve an ODE with BC with dsolve,numeric but always get the error below:

> Error, (in dsolve/numeric/BVPSolve) matrix is singular

My problem is not solving it (ie fine to do with LinearAlgebra package or similar), but why does this error occur? What is the problem with the ODE/BC that produces this error?

And is there a way of adjusting the ODE/BC to be able to solve it simply by using dsolve,numeric?

Hi everyone.

I am currently trying to write the gradient projection algorythm for an optimal control problem with Maple.

This involves calculation of the gradient of the objective function at every new iteration, which would be not a problem per se. However, in optimal control problem this last depends on state and costate variables which, in turn, are given by the system of ODEs. This system is solved numerically only. As far as I understood Maple is recalculating...

Hello,

I am trying to run maple file for k=1, k=2 ....

My do-loop did not work. What I would like to do is to solve the ODE then have new inc and solve it again.

I should have U(405) then U(770) ....

 

> restart;

> with(DEtools); with(plots);

> lambda := 0.1; delta := .5;

tau := 40;

> for k to 3 do 365*k end do;

> ode := diff(U(t), t) = -lambda(t)*U(t)*U(t);

> inc1 := U(0) = 100;

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