Re: Help on 3rd order nonlinear ode

*To*: mathgroup at smc.vnet.net*Subject*: [mg28331] Re: Help on 3rd order nonlinear ode*From*: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>*Date*: Thu, 12 Apr 2001 02:17:58 -0400 (EDT)*Organization*: Universitaet Leipzig*References*: <9b0sut$rs@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Hi, my Mathematica 4.1 gives for sol = DSolve[{(y'[x])^2 + y[x]*y''[x] + 10*y'''[x] == 10}, y[x], x] a solution and you may eliminate the additional solutions and integration constants by hand and by some "physical" assumptions. Regards Jens Jay wrote: > > I tried to solve the following third order nonlinear ode using NDSolve > in Mathematica: > > (y'[x])^2 + y[x]*y''[x] + 10* y'''[x] == 10 > > with boundary/initial conditions > > y[0] == 0, y'[0] == 0, y'[10] == 1. > > However, Mathematica says: > > NDSolve::"pcnan": "Coefficients of the differential equation are not > numbers \ or only one linear nth order ordinary differential equation > can be solved." > > Can you help me please? > > Thanks, > Jay