Items tagged with ode ode Tagged Items Feed

I am writing a procedure that takes the "output" of a call to dsolve (with the options numeric and listprocedure and without specifying a range of integration) as an argument ('dsol') together with a minimally acceptable range of integration ('tf'). The output of the procedure is either the input 'dsol' itself, if dsolve has been able to integrate from 0 to 'tf', or a modified version where the initial conditions have been modified.

Say I want to integrate an ode system [u,v,w...

I have plotted a predator/prey system using the following code and would now like to plot the same with the initial value problem of y=200, x=1000, with the end result being a graph of that one trajectory, without the phase field.  How can I do this?  Thanks.

DEtools[DEplot] ([diff(x(t), t) = 2*x(t)*(1-0.1e-3*x(t))-0.1e-1*x(t)*y(t), diff(y(t), t) = -.5*y(t)+0.1e-3*x(t)*y(t)], [x(t), y(t)], t=0 .. 10, x = 0 .. 11500, y = 0 .. 200, [[x(0) = 1000, y(0) = 200...

Hi!

I am bothered by an error that I don't understand. I am trying to write a procedure to solve numerically a delay differential equation "step by step" (for example y'(t)=y(t-1))

here is my code

restart;

y[0]:=t->t; #my initial condition on [-1,0]

p:=dsolve({D(x)(t)=y[0](t-1), x(t0)=x0}, x(t), numeric, parameters=[t0, x0]);

p(parameters=[0,y[0](0)]);

y[1]:=t->op(2,op(2,p(t)));  #y[1](t) is the value of p(t) but in a "readable" format

hi

considering the following ode

eq1 := .6740221708*(diff(f(x), x, x, x))+f(x)*(diff(f(x), x, x))+1-(diff(f(x), x))^2

i solve it by

sol := dsolve({eq1 = 0, f(0) = 0, D(f)(0) = -1.2, (D(f))(b) = 1}, numeric);

this give me one solution but i know that this ode have dual solutions. how can i found all solutions of ODE.

thanks for youe attention in advance

hi

so ill preface this by saying my knowledge of DE equations is rusty at best and my knowledge of maple even worse so this may be a stupid question. im trying to model the dynamics of a system and when i solve for the DE equation it's giving me an accleration of zero (plotting a blank graph) when it definitely shouldnt be. ive attached the worksheet. DBM-variablemass_pro.mw

Hi everyone,

I have this differential equations:

gamma1:=1;gamma2:=1;

l:=t->sqrt((x1(t)-x2(t))**2+(y1(t)-y2(t))**2);
2 2
l := t -> sqrt((x1(t) - x2(t)) + (y1(t) - y2(t)) )

DE:=[diff(x1(t),t)=(-1/(2*Pi))*gamma2*(y1(t)-y2(t))/l(t),diff(y1(t),t)=(-1/(2*Pi))*gamma1*(x1(t)-x2(t))/l(t),diff(x2(t),t)=(-1/(2*Pi))*gamma2*(y2(t)-y1(t))/l(t),diff(y2(t),t)=(-1/(2*Pi))*gamma1*(x2(t)-x1(t))/l(t)]:

I want to draw the phase portraits (x1(t...

I have two parametric equations, one for x(t), one for y(t).  Both are ODEs of order 1.  Both are implicit.  There is no way to solve explicitly for dx/dt or dy/dt.  How can I get Maple to do a plot of the solution?  I tried DEplot but apparently it demands an explicit presentation of dx/dt and dy/dt.   I have Maple12 on a Mac, but could use Maple15 on a server.

Hello everyone.

I have 2 systems of differential equations which depend on variables from each other, of course the differential variable for each is different. 

Not to get into the details of the system, since they are rather large, the problem is as follows:

I've managed to get with the parameters option a solution for x(z), in essence x(parameters=[a,b])(z). I've managed in turn to generate a procedure that would give me the avg value of x (xm...

Hey there,

how can i solve the following ODE in degree and not in radiant... numerical solution is required... im allways getting the wrong eigenfrequency.

>m*D(D(x))(t)+d*D(x)(t)+k*x(t)=sin(2*t)

Hi,

i want to use "dsolve({ODE1, IC1, IC2},numeric)" in a procedure. But it has some problems with the curly brace. Is there a special command to replace the curly brace?

Thanks

I have an ODE to solve that looks like this: 

((diff(R(r), r, r, r, r))*r^4+3*(diff(R(r), r))*r-3*(diff(R(r), r, r))*r^2+2*(diff(R(r), r, r, r))*r^3-3*R(r)+4*R(r)*n+2*R(r)*n^2-4*(diff(R(r), r))*r*n+2*(diff(R(r), r))*r*n^2+4*(diff(R(r), r, r))*r^2*n-2*(diff(R(r), r, r))*r^2*n^2-4*R(r)*n^3+R(r)*n^4)/r^4 = (-108-1362*n+2122*n^2+2019*n^3-3032*n^4+401*n^7+1192*n^6-1033*n^5-25*n^9+6*n^10-180*n^8-4128*r^(n+3)*n^3+2304*r^(n+3)*n-576*r^(n+5)*n-760*n^6*r+575*n^5*r-244*n^7*r-2108*n^3*r-11616*r^(n+3...

Whoever is in charge of the question post management, please do not delete my question again without even notifying me. I have deleted the original post (which was a follow-up question to an old thread) so that my question can be viewed by others as a fresh post. Thank you!

Now to the question:

I am trying to solve a fourth-order ODE. Two of the boundary conditions are y(1)=0 and diff(y(x),x)=0 at x=1. The other two boundary conditions are y(x) and diff(y(x...

Hello.

for one of my projects I require to solve differential equations I have obtained from an euler-lagrange system.

I solved them and obtained values of angles and their derivatives as listprocedures. I want however to be able to calculate values for different speeds noted as vx2 and vy2 as well as the angle of the speed verctor wich would be in that case arctan(vy2/vx2). It doesn't seem however that maple is going to do that. It gives me a pretty huge message...

Hi, I am trying to solve the following differential systems using dsolve numeric but there is something wrong with my code.

I am fairly new to Maple and cant work out why it is telling me that it doesnt work. COuld somebody help me?

DifferentialSystem := {diff(r(t),t$2)-r*(diff(theta(t),t)^2=-1000/r^2 ,
                            r(diff(theta(t),t$2)+2(diff(r(t),t)*(diff(theta(t),t)=0,
                            r(0)=sqrt(65), theta(0)=1.446...