parisse a écrit :Run proot(expression,n) where n is an integer for more precision.
Nice one! Thanks. I have more precision now
. BTW, can you remind me again how to express a symbol "x" as an algebraic element corresponding to a root (modulo conjugate) of a polynomial. I forgot this. So for instance I want to use
x=some root of f(x) (encoded as algebraic integer, not a float)
then
x+conj(x) (if this is possible in giac) and eventually feed it to pari and check what is the minimal polynomial of such a (real) algebraic number.
Edit: Actually.. I'm an idiot. Nevertheless it is interesting for me to know how to represent algebraic numbers in giac. For my specific case (minimal polynomial of say the real part of an algebraic number) I can take the resultant of f(x), f(z-x) over x, where f(x) is the minimal polynomial of the algebraic number I am interested in. From this resultant (polynomail with variable z) I can deduce the minimal polynomial of the real part (or twice of it, but there is another trick to get the real part).