Re: Re: For help about NSolve

*To*: mathgroup at smc.vnet.net*Subject*: [mg88343] Re: Re: For help about NSolve*From*: "Jean-Marc Gulliet" <jeanmarc.gulliet at gmail.com>*Date*: Fri, 2 May 2008 03:43:59 -0400 (EDT)*References*: <fvbr3m$pj2$1@smc.vnet.net> <4819E6B5.4080304@gmail.com>

2008/5/2 wtpdrj <45417003 at 163.com>: > > > This is the result. > > > why ? [Cross-posted to comp.soft-sys.math.mathematica aka MathGroup] ode = y''[x] + y[x]*(1 + y'[x])^(3/2) nsol = NDSolve[{ode == 0, y[0] == 0, y[1] == 0}, y, {x, 0, 1}] Plot[y[x] /. nsol[[1]], {x, 0, 1}] Table[y[x] /. nsol[[1]], {x, 0, 1, 0.1}] Works fine on my system. $Version "6.0 for Mac OS X x86 (64-bit) (February 7, 2008)" See http://homepages.nyu.edu/~jmg336/mathematica/helpaboutndsolve.pdf I suspect that you are using a version prior 6.0 and that NDSolve has been improved meanwhile. > Thanks again. > > å?¨2008-05-01ï¼?"Jean-Marc Gulliet" <jeanmarc.gulliet at gmail.com> å??é??ï¼? > > > > xxhai wrote: > > > Differential Equation: > > y[x]''+y[x]*{(1+y[x]'^2)}^(3/2)=0 > > > > aboundery condition: y[0]=0, y[1]=0 > > > > For Numerical Solution ? > > > > why Mathematica can't solve the Equation with the initial condition ? > > > > please give the correct program for differential equation. > > > > > > thank you a lot. > > (* Here is an example of how to use NDSolve and its result *) > nsol = NDSolve[{y''[x] + y[x]*((1 + y'[x]^2))^(3/2) == 2, y[0] == 0, > y[1] == 0}, y, {x, 0, 1}] > Plot[y[x] /. nsol[[1]], {x, 0, 1}] > Table[y[x] /. nsol[[1]], {x, 0, 1, 0.1}] > > (* As given, your original equation has y(x) = 0 as solution *) > nsol = NDSolve[{y''[x] + y[x]*((1 + y'[x]^2))^(3/2) == 0, y[0] == 0, > y[1] == 0}, y, {x, 0, 1}] > Plot[y[x] /. nsol[[1]], {x, 0, 1}] > Table[y[x] /. nsol[[1]], {x, 0, 1, 0.1}] > > Regards, > -- Jean-Marc > > -- Jean-Marc