RootIntervals

RootIntervals[{poly₁, poly₂, ...}]
gives a list of isolating intervals for the real roots of any of the poly_i, together with a list of which polynomials actually have each successive root.

RootIntervals[poly]
gives isolating intervals for real roots of a single polynomial.

RootIntervals[polys, Complexes]
gives bounding rectangles for complex roots.

MORE INFORMATION

The coefficients of poly must be integers or rationals.

An isolating interval for a root a of a polynomial poly is an interval where the only root of poly contained in the interval is a.

If a root is real, the isolating interval is an open real interval, or a point. If a root is not real, the isolating interval is an open rectangle, disjoint from the real axis.