Date: Dec 29, 2009 1:24 AM
Author: André Hautot
Subject: algebraic numbers

x= Sqrt[2] + Sqrt[3] + Sqrt[5]   is an algebraic number

MinimalPolynomial[Sqrt[2] + Sqrt[3] + Sqrt[5], x]

returns the polynomial :  576 - 960 x^2 + 352 x^4 - 40 x^6 + x^8  as 
expected

Now suppose we only know the N first figures of x (N large enough), say 
:  N[x,50] = 5.3823323474417620387383087344468466809530954887989

is it possible to recognize x as a probably algebraic number and to 
deduce its minimal polynomial ?

Thanks for a hint,
ahautot