Re: Do loop is faulty
- To: mathgroup at smc.vnet.net
- Subject: [mg55415] Re: Do loop is faulty
- From: Paul Abbott <paul at physics.uwa.edu.au>
- Date: Tue, 22 Mar 2005 03:51:06 -0500 (EST)
- Organization: The University of Western Australia
- References: <d1jfsj$sa4$1@smc.vnet.net> <d1lvsb$7ub$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
In article <d1lvsb$7ub$1 at smc.vnet.net>,
"dumb_founded" <andreajagger_8 at hotmail.com> wrote:
> Oops, sorry, I mistyped the code. It should read:
>
> Array[c,10];
> Do[c[i]=NIntegrate[a[i]*x*Sin[b[i]*x],{x,0,b[i]}],{i,1,10}]
Others have answered your original question -- and you did mention that
you were trying to use Mathematica for numerical analysis. However, you
should realise that Mathematica can compute the required integrals in
closed form for arbitrary a and b:
int[a_,b_] = Integrate[a x Sin[b x], {x, 0, b}]
so there is no need to use NIntegrate.
> dumb_founded wrote:
> > I define array a[i] and array b[i] of dimension 10. Then I go
> through
> > the following Do loop, or try to, that is.
> >
> >
> > Array[c,10];
> > Do[c[i]=NIntegrate[a[i]*x*Sin[b[i]*x],{x,0,b[i]}]
> >
> > I get numerous error messages saying that b[i] is not a valid limit
> of
> > integration.
> >
> > This is sheer headache. I will never try to use Mathematica for
> > numerical analysis again.
> >
> > All your efforts on this matter are sincerely appreciated.
> >
> >
> >
> > Thanks
>
--
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