The Math Forum

Search All of the Math Forum:

Views expressed in these public forums are not endorsed by NCTM or The Math Forum.

Math Forum » Discussions » Software » comp.soft-sys.matlab

Notice: We are no longer accepting new posts, but the forums will continue to be readable.

Topic: ode45 help
Replies: 2   Last Post: Dec 7, 2012 9:13 AM

Advanced Search

Back to Topic List Back to Topic List Jump to Tree View Jump to Tree View   Messages: [ Previous | Next ]

Posts: 69
Registered: 2/22/12
Re: ode45 help
Posted: Dec 7, 2012 9:13 AM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply

"mojtaBa malekpour" <> wrote in message <k5j820$iq6$>...
> why matlab can't solve this?
> function dy = ffffd(t,y)
> dy = zeros(4,1); % a column vector
> dy(1) =y(2);
> dy(2) =-81276055.762*cos(atan((0.05*sin(523.5988*t)+0.12*sin(y(3)))/(-y(1)+0.05*cos(523.5988*t)+0.12*cos(y(3)))))*([[y(1)-0.05*cos(523.5988*t)-0.12*cos(y(3))]^2+[0.05*sin(523.5988*t)+0.12*sin(y(3))]^2]^0.5-0.0005)^1.5;
> dy(3) =y(4);
> dy(4) =171687.934*sin(y(3)-523.5988*t)+1357293887.572*sin(y(3)-atan((0.05*sin(523.5988*t)+0.12*sin(y(3)))/(-y(1)+0.05*cos(523.5988*t)+0.12*cos(y(3)))))*([[y(1)-0.05*cos(523.5988*t)-0.12*cos(y(3))]^2+[0.05*sin(523.5988*t)+0.12*sin(y(3))]^2]^0.5-0.0005)^1.5+122.868*cos(y(3));
> [T,Y] = ode45(@ffffd,[0 2.784],[0.1705 0 0 0]);

You have some large numbers in there... perhaps convergence/divergence issues?
It looks like it tries to solve it, just takes a long time.

Date Subject Author
Read ode45 help
mojtaBa malekpour
Read Re: ode45 help
Read Re: ode45 help

Point your RSS reader here for a feed of the latest messages in this topic.

[Privacy Policy] [Terms of Use]

© The Math Forum at NCTM 1994-2018. All Rights Reserved.