简介:ThebasicprincipleofintervalarithmeticandthebasicalgorithmoftheintervalNewtonmethodsareintroduced.Theprototypealgorithmcannotfindanyzeroinanintervalthathaszerosometimes,thatis,itisinstable.Sotheprototyperelaxationprocedureisimprovedinthispaper.Additionally,animmediatetestoftheexistenceofasolutionfollowingbranch-and-boundisproposed,whichavoidsunwantedcomputationsinthoseintervalsthathavenosolution.ThenumericalresultsdemonstratthattheimprovedintervalNewtonmethodissuperiortoprototypealgorithmintermsofsolutionquality,stabilityandconvergentspeed.