Re: ODEs and phase portraits

*To*: mathgroup at smc.vnet.net*Subject*: [mg14773] Re: ODEs and phase portraits*From*: Dr Phillip Kent <p.kent at ic.ac.uk>*Date*: Sat, 14 Nov 1998 03:08:04 -0500*Organization*: Imperial College*References*: <728kp1$ehc@smc.vnet.net> <72fad6$feq$2@dragonfly.wolfram.com>*Sender*: owner-wri-mathgroup at wolfram.com

Kevin J. McCann wrote: > > Try this one: > > ............................... > > phantomlord at my-dejanews.com wrote in message <728kp1$ehc at smc.vnet.net>... > >I am trying to write a function such that I have the following ODE: > >x''(t)+epsilon*(x(t)^2-1)*x'(t)+x(t)==0 [1] where epsilon is to be one > >of the parameters in the function. I want to beable to draw out the > >phase portraits for the equation for different values of epsilon. > > > .............................. > >Perhaps there is a built in function that will allow me to do this? If > >not do, can anybody suggest another way to do this? > > > >Also after plotting the trajectory is there any way to determine the > >direction of it in Mathematica? > > > >thanks for you time. > >Paul > > I have prepared a little code package to make trajectories and phase portraits easier to handle - please take a look: http://metric.ma.ic.ac.uk/dynamics ----------------------------------+---------------------------- Dr Phillip Kent | tel: +44 (0)171 594 8503 The METRIC Project | fax: +44 (0)171 594 8517 Mathematics Department | Imperial College | p.kent at ic.ac.uk London SW7 2BZ, U.K. | http://metric.ma.ic.ac.uk/ ----------------------------------+---------------------------- "In designing tools we are designing ways of being"