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 > -- Paul Abbott Phone: +61 8 6488 2734 School of Physics, M013 Fax: +61 8 6488 1014 The University of Western Australia (CRICOS Provider No 00126G) 35 Stirling Highway Crawley WA 6009 mailto:paul at physics.uwa.edu.au AUSTRALIA http://physics.uwa.edu.au/~paul