NSolve and SplineFit
- To: mathgroup at smc.vnet.net
- Subject: [mg44117] NSolve and SplineFit
- From: mizrandir at hotmail.com (Mizrandir)
- Date: Thu, 23 Oct 2003 07:15:16 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
Hello.
I have a list of (x,y) points. They are equally spaced in the x-axis
so I have decided to use SplineFit in order to have a function I can
evaluate in whichever intermediate point I like. Up till there
everything's ok: I can evaluate the function, I can plot it and I can
even use NIntegrate. Here is more or less what I've done:
In[1]:= <<NumericalMath`SplineFit`
In[2]:= fun=SplineFit[{{4.55},{4.98},{25.42},{73.36},{150.85},{260.07}},Cubic];
In[3]:= fun[2.3]
Out[3]= {36.863}
In[4]:= NIntegrate[fun[x][[1]],{x,0,5}]
Out[4]= 376.97
My problem comes when I try to do something like:
NSolve[fun[x] == 50,x] or NSolve[fun[x][[1]] == 50,x]
and Mathematica doesn't allow me to do this.
Any suggestions are welcome, miz.