Re: How do you input a solution from FindRoot into another equation?
- To: mathgroup at christensen.cybernetics.net
- Subject: [mg754] Re: How do you input a solution from FindRoot into another equation?
- From: dm5579 at glibm19.cen.uiuc.edu (Demetri Mouratis)
- Date: 13 Apr 1995 01:43:59 GMT
- Organization: UIUC Engineering Workstation Labs
In article <3mfauj$l4o at news0.cybernetics.net>, rdack at acs.ucalgary.ca (Robert Dack) writes:
|>
|> Can someone tell me how to take the output from the FindRoot
|> cammand and input it into the next command line? The output
|> comes out in the form { x -> 2.435 }, so the usual [%] command on
|> the next line won't work.
|>
|> Any help in this area would be appriciated
|>
|> R Dack rdack at acs.ucalgary.ca
|>
|>
|>
|>
Sure.
The FindRoot command, returns a list as a solution. In your case the list is
{x -> 2.435}. You want to get at an element within that list, the root. The
Mathematica Part command allows you to do this. Here's an example:
In[1]:=
FindRoot[Sin[x]==0,{x,3}]
Out[1]:=
{x -> 3.14159}
In[2]:=
%[[1]]
Out[2]:=
x -> 3.14159
In[3]:=
%[[2]]
Out[3]:=
3.14159
You can combine the two steps into %[[1,2]] and get the same thing.