isolating intervals for real roots of a polynomial - Maple Help

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realroot - isolating intervals for real roots of a polynomial

Calling Sequence

realroot(poly, widthgoal)




univariate polynomial with integer coefficients



(optional) maximal size of each isolating interval



The command realroot(poly, widthgoal) returns a list of isolating intervals for all real roots of the univariate polynomial poly. The width of the interval is less than or equal to the optional parameter widthgoal, a positive number.  If widthgoal is omitted, the most convenient width is used for each interval returned.


Each interval is returned as a list of two rational numbers. The list a&comma;a represents the single point a.  The list a&comma;b with a<b represents the open real interval defined by a and b. Multiplicity information is not included. The denominators of a and b are integer powers of 2.


The intervals are sorted in ascending order.


The algorithm behind realroot uses Descartes' rule of signs.





See Also

fsolve, RootFinding[Isolate], roots, Roots, solve



Loos and Collins, Computer Algebra, B. Buchberger, ed.

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