Re: refer to the result of FindRoot[ ]
- To: mathgroup at smc.vnet.net
- Subject: [mg61558] Re: refer to the result of FindRoot[ ]
- From: David Bailey <dave at Remove_Thisdbailey.co.uk>
- Date: Sat, 22 Oct 2005 00:36:07 -0400 (EDT)
- References: <dja24u$fg7$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
perimeterbow at gmail.com wrote:
> FindRoot[] returns result in this format {x->2.123}, how can I get rid
> of the x-> so I can use the number directly to automate calculation
> flow?
> Thanks.
>
Hello,
x/.FindRoot[.....]
This works because FindRoot returns a list of transformation rules -
which is just the thing for use in a replacement.
For example:
x/.FindRoot[Sin[x]\[Equal]Cos[x],{x,0}]
The thing to realise is that often you don't really want the value of x,
but the value of some expression involving x - say f[x]. In that case,
you can do the whole thing in one step:
f[x]/.FindRoot[Sin[x]\[Equal]Cos[x],{x,0}]
David Bailey
http://www.dbaileyconsultancy.co.uk