Zero crossing

[expikx]

hey all,

i´ve got some problems with the determination of zero points of a fitted
function.

this is what i have done:

1) data input with A=load("-ascii", "file.csv")

2) naming my data with x = A(:,1) and y = A(:,2)

3) fitting with P=polyfit(x,y,4)

5) S=polyval(P,x) to get the fitting polynome (am i right?)

for my next step in need the zero crossing point of my fitted function. By
typing roots(S) i just get imaginary solutions, but there are real
solutions! I also tried the command fzero and nothing happens :-(

may you help me?

thx a lot

cheers,
expikx



--
View this message in context: 
http://octave.1599824.n4.nabble.com/Zero-crossing-tp4649020.html
Sent from the Octave - General mailing list archive at Nabble.com.