       Re: Differential eqn. with interpolated coeficients

• To: mathgroup at smc.vnet.net
• Subject: [mg29187] Re: [mg29158] Differential eqn. with interpolated coeficients
• From: Ben Jacobson <bjacobson at illumitech.com>
• Date: Sat, 2 Jun 2001 05:54:41 -0400 (EDT)
• Sender: owner-wri-mathgroup at wolfram.com

```Works fine for me.  I would guess you have a syntax error.

In:=
p[x_] = Interpolation[Table[{j, Sin[j]}, {j, 0, 6, .6}]][x]

Out=
InterpolatingFunction[{{0., 6.}}, "<>"][x]

In:=
q[x_] = Interpolation[Table[{j, j*Cos[j]}, {j, 0, 6, .6}]][x]

Out=
InterpolatingFunction[{{0., 6.}}, "<>"][x]

In:=
NDSolve[{y''[x] + p[x]y'[x] + q[x] == 0, y == .5, y' == .3}, y, {x, 0,
6}]

Out=
{{y -> InterpolatingFunction[{{0., 6.}}, "<>"]}}

Ben Jacobson
Illumitech Inc.

At 04:15 AM 6/1/01 -0400, you wrote:
>I need to solve a ordinary second order differential equation, of the
>type y''[x] + P[x] y'[x] + Q[x] == 0, where the coefficients P[x] and
>Q[x] are an interpolating function (or a table of numerical data).
>
>I have tried with NDSolve, but it seems to admit only an interpolating
>function for Q[x], but not for P[x]. Does any one know what could I do?
>
>Regards,
>
>Daniel Arteaga
>
>

```

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