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.

```

• Prev by Date: Re: Accuracy and Precision
• Next by Date: Re: How do you input a solution from FindRoot into another equation?
• Previous by thread: Re: PolarPlot ???
• Next by thread: Re: How do you input a solution from FindRoot into another equation?