Re: Not a valid limit in NIntegrate ???
- To: mathgroup at smc.vnet.net
- Subject: [mg3144] Re: Not a valid limit in NIntegrate ???
- From: whitic at rpi.edu (whitic)
- Date: Tue, 6 Feb 1996 22:51:03 -0500
- Organization: Rensselaer Polytechnic Institute, Troy NY, USA
- Sender: owner-wri-mathgroup at wolfram.com
a_kowald at chemie.fu-berlin.de (Axel Kowald) wrote:
>Hi
>FindRoot[NIntegrate[t,{t,rho,100}]==1,{rho,99}]
>NIntegrate[t,{t,rho,100}] /. rho->99
>When I'm using one of the above constructs either on a Mac or under Unix
>running Mathematica 2.2 I get the following error message:
>NIntegrate::nlim: t=rho is not a valid limit of integration
>Why does it complain ?? Any ideas ??
>Many thanks
> Axel Kowald
Try using the built in Secant method for the FindRoot routine.
Mathematica uses this method when FindRoot is called with the
following syntax:
FindRoot[ f[x]==g[x], {x,x1,x2}]
For the problem in question, you can use the command:
FindRoot[ NIntegrate[t,{t,rho,100}]==1,{rho,99,100}]
with this, Mathematica does not complain, since it does not have to
evaluate, analytically the Jacobian of this numerical function.
Hope this helps,
Chris Whiting
whitic at rpi.edu
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