Re: Differential Equation, pendulum, change of variable plot

*To*: mathgroup at smc.vnet.net*Subject*: [mg99304] Re: Differential Equation, pendulum, change of variable plot*From*: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>*Date*: Sat, 2 May 2009 05:59:41 -0400 (EDT)*References*: <gtbtrf$249$1@smc.vnet.net>

Hi, beside the fact, that your equation is unreadable, but it should be a differential equation second order for a pendulum and if it is non-autonomous you must look to w[n*Omega] when Omega is the frequency of the driving force and n a natural number. Regards Jens gareth wrote: > Hello, thanks for taking the time to help sort out my query. > > I am in the middle of investigating non linear pendulum. > The equations of motion are > w'[t]=-(1/q)w[t]-Sin[=CE=B8[t]] + g Cos[wD t] > > Theta is the displacement, w the frequency, wD the driving frequency an= d g the drive amplitude. > Basically so far a I have plotted w vs theta to show chaos, however now= I want to create a bifurcation diagram, > like this http://www.physics.drexel.edu/~gbyrne/Bif_g.jpg > This is done as far as I know is plotting w at the start of every drive= cycle against g. > But I cant figure out how to do this, > maybe so sort of Do loop with the NDSolve of the differential equation. > Any help would be much appreciated >