Re: nonlinear differential equation
- To: mathgroup at smc.vnet.net
- Subject: [mg54725] Re: nonlinear differential equation
- From: Peter Pein <petsie at arcor.de>
- Date: Mon, 28 Feb 2005 03:27:13 -0500 (EST)
- References: <cvhequ$qft$1@smc.vnet.net> <200502250618.BAA02402@smc.vnet.net> <cvrqae$p3s$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
DrBob wrote:
> Yikes!!! Good luck inverting the functions involved.
>
> Off[Solve::verif, Solve::tdep]
> deqn = Derivative[2][s][t] -
> a*s[t]^2 - b*s[t] - c == 0;
> ddeqn =
> ((Integrate[#1, t] & ) /@
> Expand[Derivative[1][s][t]*
> #1] & ) /@ deqn
> s /. DSolve[{%}, s, t]
> (-c)*s[t] - (1/2)*b*s[t]^2 -
> (1/3)*a*s[t]^3 +
> (1/2)*Derivative[1][s][t]^
> 2 == 0
...
As you can see, the conditions s[0]==0 and s'[0]==v0 hold only if v0==0.
--
Peter Pein
Berlin
- References:
- Re: nonlinear differential equation
- From: "Jens-Peer Kuska" <kuska@informatik.uni-leipzig.de>
- Re: nonlinear differential equation