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I want to solve a set of ODE equations numerically,there is 5 equations with certain boundary conditions,please help me,what kind of dsolve order could i use? when i use dsolve({sys,bcs}type=numeric) i get an error that say me:system must be entered as a set of equations! how can i solve it?

Hello,

I'm having problems to do somehting that I guess maple should be able to do. I am solving numerically a 2nd order equation. Then Dsolve gives me the function and its first derivative.

Is there not a way to plot 2nd and 3rd derivatives??
Of course I have thought of getting f'' as a funtion of f' and f through the differential equation, but in my case that involves a complicated analytical development, and I precisely want to verify that I didnt do...

Hi,

 

Is there a way to generate Java or C code to implement a general nth order linear ordinary differential equation?

I am looking to be able to send the coefficients and have it compute the time waveform given initial conditions.

 

Regards.

i am looking for a command adjoint a ODE, to check whether my understanding of adjoint correct or not, when i find one example different from my understanding as follows

u*diff(Y,t) - diff(U,t) + diff(y,t)*U = 0 where uppercase and lowercase are different

why after adjoint is

Y -> -u*diff(lambda,t) - diff(u,t)*lambda = miu1
U -> diff(lambda,t) + diff(y,t)*lambda = miu2

why not

Y -> u*diff(lambda,t) = miu1
U -> -diff(lambda,t) + diff(y,t)*lambda = miu2

Okay, so I think this is simple, but I cannot find the command.

 

I get a numeric solution for a system of ODEs, with variables a function of t. Now, I know I can use the sol(t) command to give me the values of my variables at specific values of t. But, how do I get the values of t for specific variable values. There has to be a more efficient way than just plugging in values for t until I come to the answer.

Thanks!

 

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

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

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