Items tagged with ode ode Tagged Items Feed


     I wish to plot the trajectory of a ball, and I set up my three differential equations and solved them numerically. I can graph the x, y, z components but I can’t figure out how to plot 3D space curve of this (and animate it if possible).

I used dsolve, numeric rtk45, so the output is [t, x, x’, y, y’, z, z’] so I tried to assign the second (and 4rth and 6h) term in the list to a function

i got error while running the code. 

restart; de := diff(f(y), y, y, y, y)+2*W*(diff(f(y), y, y, y))^2+3*(diff(f(y), y, y, y, y))*(diff(f(y), y, y))-(M*M)*(diff(f(y), y, y))+G*(diff(theta(y), y, y))+B*(diff(phi(y), y, y)) = 0, diff(theta(y), y, y)+Nb*(diff(theta(y), y))*(diff(phi(y), y))+Nt*(diff(theta(y), y))^2 = 0, diff(phi(y), y, y)+Nb*(diff(theta(y), y, y))/Nt = 0, f(h1) = (1/2)*F, f(h2) = -(1/2)*F, (D(f))(h1) = -1, theta(h2) = 1, phi(h2) = 1, (D(f)...

Hello every one,
I got an error while trying to solve numerically a nonlinear system of odes using 
the dsolve command. This error is very common,
"Error, (in dsolve/numeric/bvp) initial Newton iteration is not converging".
I tried the different technique explained in

i have a differencial equation and use DEplot but it does't plot anything.

i have uploaded an image of what im doing


plotting problem....

September 18 2012 J4James 175

This question was asked before but because of the curiosity, I 

bring it in the light again. We have a system of odes


a := 1; b := .5; d := 1; omega := .4; h1 := 1+a*cos(x); h2 := -d-b*cos(x+omega);

F := Q-1-d;

de:={alpha*(diff(f(y), y, y, y, y))+G*(diff(theta(y), y, y))+B*(diff(phi(y), y, y))

+6*beta*(diff(f(y), y, y))*(diff(f(y), y, y, y))^2+3*beta*(diff(f(y), y, y, y, y))*

(diff(f(y), y, y))^2 = 0,

Hello every one,

I am trying to solve a system of 5 odes numerically but I get an error

"unable to convert to an explicit first-order system".

Please have a look and guide me through the problem.


For example 

y'''-y''+2y'=0 ; y(0) = 1, y'(0)=0, y''(0) =0
ode := diff(f(x), x, x, x)-(diff(f(x), x, x))+2*(diff(f(x), x))
the I.C. for y''(0) =0 is ?
Please give the format.
After numerically solving an ODE, I want to save the solutions as a .dat file. I got this from the internet net for PDES and tried by adapt it to odes using dsolve. But I get this: Error, `sol` does not evaluate to a module 
PDE := diff(u(x, t), t, t)-(diff(u(x, t), x, x))+.2(diff(u(x, t), t))-1/2*(u(x, t)-u(x, t)^3) = 0;
 IBC := {u(-15, t) = -1, u(15, t) = 1, u(x, 0) = tanh(x), (D[2](u))(x, 0) = -1/cosh(x)^2}; sol := pdsolve(PDE, IBC, 'numeric', u(x, t...

I'm trying to use Maple to assist me in my homework.  To me, TI & MsMath are more intuitive than Maple, however, i have a Maple license.  That said, how do i specify an initial condition while trying to solve an ODE using dSolve?  For TI, i would enter:

deSolve(x’=x/25 and x(0)=20,t, x)

... and be done with it.  I suspect that i have to use diff() to assign x/25 as the f(x) of y'.  However, how do i specify the initial condition?

I want to solve a diff eqn, but it is giving absurd answer.

> ode := diff(f(x), x, x) = (Phi(x)-lambda)*f(x);
d / d \
--- |--- f(x)| = (Phi(x) - lambda) f(x)
dx \ dx /
> dsolve(ode);
/ / / d / d \\\ \
f(x) = DESol|{ (-Phi(x) + lambda) _Y(x) + |--- |--- _Y(x)|| }, {_Y(x)}|
I am dealing with a problem in engineering mechanics, but my when using maple to solve the governing nonlinear equation with 4 bcs, I meet with error. 
Error, (in dsolve/numeric/bvp) initial Newton iteration is not converging

my code is :
deq := diff(y(x), `$`(x, 4)) = -.364*(diff(y(x), x))^2*(diff(y(x), `$`(x, 2)))+1.74*10^(-7)
bc := y(0) = 0, (D(y...

I am new to maple. The problem I am facing is to get a non-trivial

solution of a system of odes. But maple gve me only trivial solution.


# The system of odequations I am trying to solve is (Please note that in the bcs phi is alpha.)



# The solution of the above sys of odes is of the form, (note x3=z, its just a typo)

How can I use the command outputs DEtools [convertsys] for solving the system of differential equations? I know that maple can solve the system directly. But most of the examples can be seen in other systems (MathCad, MatLab ..) reduce the system to a system of first order equations. And I would like to implement, "translate" into Maple in this way. Is there a command that allows it? Do I need to implement a procedure?



I am a PhD scholar at the University of Queensland. I am reviweing a paper titled as "A similarity solution for laminar thermal boundary layer over a flat plate with a convective surface boundary condition"(the pdf is available online). In this paper the author has written a MAPLE code. I copied the same code in MAPLE but could nt succedded. The author used the Runge Kutta RK5 Method to solve the model.

Please help me to solve the same model...


consider the following ode


subject to thease boundary condition



b= infinity (in computational domain b=10 is acceptable )

the exact solution of ode is


but when i want to solve it with Dsolve, maple get the zero. how can i use this ode in maple



5 6 7 8 9 10 11 Last Page 7 of 16