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Re: For help about NSolve

  • To: mathgroup at smc.vnet.net
  • Subject: [mg88327] Re: [mg88305] For help about NSolve
  • From: "W_Craig Carter" <ccarter at mit.edu>
  • Date: Fri, 2 May 2008 03:41:05 -0400 (EDT)
  • References: <200805010720.DAA26104@smc.vnet.net>

Hello xxhai,
It does give a solution (perhaps not unique), but not a very interesting one:

ode = D[y[x], {x, 2}] + y[x] (1 + D[y[x], x]^(3/2))
nsol = NDSolve[{ode == 0, y[0] == 0, y[1] == 0}, y[x], x]
Plot[y[x] /. nsol, {x, 0, 1}]
Table[y[x] /. nsol, {x, 0, 1, .1}]


However

ode = D[y[x], {x, 2}] + y[x] (1 + D[y[x], x]^(3/2))
nsol = NDSolve[{ode == 0, y[0] == 0, y[1] == 1}, y[x], x]
Plot[y[x] /. nsol, {x, 0, 1}]

is more interesting---perhaps the question is in regard to your
boundary conditions?

If not, take a look at the option Method and the final example in
NDSolve (6.0 Documentation)


Best Wishes, Craig
On Thu, May 1, 2008 at 3:20 AM, xxhai <45417003 at 163.com> 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.
>
>
>



-- 
W. Craig Carter


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