Re: Integrating Interpolating function
- To: mathgroup at smc.vnet.net
- Subject: [mg120701] Re: Integrating Interpolating function
- From: DrMajorBob <btreat1 at austin.rr.com>
- Date: Thu, 4 Aug 2011 02:53:16 -0400 (EDT)
- Delivered-to: l-mathgroup@mail-archive0.wolfram.com
- References: <201108031107.HAA10850@smc.vnet.net>
- Reply-to: drmajorbob at yahoo.com
> s = NDSolve[{y'[x] == y[x] Cos[x + y[x]], y[0] == 1}, y, {x, 0, 30}]
> NIntegrate[t*s[t], {t, 0, 30}]
>
> does what you are looking for.
No, it doesn't. Instead, you need something like
s = y /. First@
NDSolve[{y'[x] == y[x] Cos[x + y[x]], y[0] == 1}, y, {x, 0, 30}];
NIntegrate[t*s[t], {t, 0, 30}]
46.9655
Bobby
On Wed, 03 Aug 2011 18:20:37 -0500, Oliver Ruebenkoenig
<ruebenko at wolfram.com> wrote:
> On Wed, 3 Aug 2011, math_new wrote:
>
>> Hi,
>>
>> I solve a system of differential equations using NDSolve up to time
>> t_end. which gives me something like
>>
>> sol = {f->InterpolatingFunction}
>>
>> Now I want to do an integral like that
>>
>> Integrate[t*f[t],{t,0,tend}]
>>
>> but it won't be computed. What am I doing wrong?
>>
>> Cheers
>>
>>
>
> Hi
>
> s = NDSolve[{y'[x] == y[x] Cos[x + y[x]], y[0] == 1}, y, {x, 0, 30}]
> NIntegrate[t*s[t], {t, 0, 30}]
>
> does what you are looking for.
>
> Hth,
> Oliver
>
--
DrMajorBob at yahoo.com
- References:
- Integrating Interpolating function
- From: math_new <dom.woe@gmail.com>
- Integrating Interpolating function