Re: Help with solving ODE

*To*: mathgroup at smc.vnet.net*Subject*: [mg81793] Re: Help with solving ODE*From*: "Kevin J. McCann" <kjm at KevinMcCann.com>*Date*: Wed, 3 Oct 2007 06:13:03 -0400 (EDT)*References*: <fdvdq7$sul$1@smc.vnet.net>

First, you should learn to use Mathematica. This one is pretty basic. Try DSolve[y''[t]+b y'[t]==c,y[t],t] Pioneer1 wrote: > Hi, > > Can anyone help solve this linearized differential equation: > > Iy'' + ky' = 2GMmd/a^2 > > Primes are time derivates of y (=theta=excursion angle). Is it > possible to solve this for the initial conditions y(0)=0 and y'(0)=0? > > I got the solution at sci.math for the non-linear version and I want > to compare the two. Here's the link to sci.math thread: > > http://groups.google.com/group/sci.math/browse_thread/thread/a6ee2f782df09625/53cf5573d354a3ab#53cf5573d354a3ab > > Further information is also available at sci.physics.research > > http://groups.google.com/group/sci.physics.research/browse_thread/thread/d391940cc173f9dc/eed90e6c3fee0edc#eed90e6c3fee0edc > > Parameters are: > > >>y = theta = excursion angle in radians >>A = I = moment of inertia = 13,138,117.34 g cm^2 >>B = R = damping = for now I assume this to be zero >>C = k = torsion constant = 724.68 g cm^2 sec^-2 >>d = moment arm = 93.09 cm >>D = 2GMmd = 2 * 6.67*10^-8 * 158100 * 729.8 * 93.09 = 1432.82 >>a = distance between weights = 22.10 cm > > > I would truly appreciate help with this. Thanks > >