This is documentation for Mathematica 6, which was
based on an earlier version of the Wolfram Language.
View current documentation (Version 11.1)

RootIntervals

RootIntervals[{poly1, poly2, ...}]
gives a list of isolating intervals for the real roots of any of the polyi, 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.
  • 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.
  • Multiple roots give multiple entries in the second list generated by RootIntervals.
Get isolating intervals, together with a list of which polynomial has which root:
In[1]:=
Click for copyable input
Out[1]=
 
The isolating intervals are always specified by exact rationals:
In[1]:=
Click for copyable input
Out[1]=
New in 6