Author 
Comment/Response 
Vassilis

11/24/07 04:56am
Hi All,
I'd like some help with respect to a problem I have with the FindRoot, NSolve and FindInstance functions.
I define the function f as follows:
f[x_]:={
y/.FindRoot[y^3+1==x,{y,x}][[1]]
}[[1]]
f[x] returns the root of the equation y^3 + 1 == x, i.e. the value (x1)^(1/3). f[x] has obviously a
unique root at x=1.
If I now try to find f[x]'s root with FindRoot, for example like
FindRoot[f[x]==0,{x,3}]
Mathematica (v 5.2) returns error messages and no solution. The same happens if I use instead NSolve
or FindInstance. Can you guys explain why this happens and suggest a remedy? Needless to say, the actual problem
I try to tackle involves much more complicated functions...
Thanks,
Vassilis
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