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)
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.
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).