Re: Simple Q: How to give computed results from NSolve to a new
- To: mathgroup at smc.vnet.net
- Subject: [mg87273] Re: Simple Q: How to give computed results from NSolve to a new
- From: Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com>
- Date: Sun, 6 Apr 2008 06:43:01 -0400 (EDT)
- Organization: The Open University, Milton Keynes, UK
- References: <ft7gfo$br6$1@smc.vnet.net>
loveinla at gmail.com wrote:
> I have solved a system of equations by NSolve. And for instance, it returns the results as
> Root={{x->1,y->2}}.
>
> And now I want to use the computed results, say x & y to define a new variable
> Z=x^2+sqrt(xy).
>
> How should I use computed x and y to define the new variable Z?
Assuming you use the correct syntax to define the variable z, you just
have to apply the transformation rules (i.e. "something" -> "something
else")via the replacement operator /. as in the following example:
In[1]:= sol = {{x -> 1, y -> 2}}
Out[1]= {{x -> 1, y -> 2}}
In[2]:= {x, y} /. sol[[1]]
Out[2]= {1, 2}
In[3]:= z = x^2 + Sqrt[x*y] /. sol[[1]]
Out[3]= 1 + Sqrt[2]
For more information, see
http://reference.wolfram.com/mathematica/ref/ReplaceAll.html
http://reference.wolfram.com/mathematica/tutorial/ApplyingTransformationRules.html
Regards,
-- Jean-Marc