Assume that we have
where is an interval and
should lie in an arbitrary range. The procedure `Filtre_Arc_Cos` allows to update the range for . It returns
-1 is and are incompatible, 0 otherwise. Its syntax is:

int Filtre_Arc_Cos(INTERVAL &U,INTERVAL &beta)A similar procedure exist for the inverse sine with

The procedure `Arc_Cos_Multiple` allows to determine all
possible ranges
for , assuming that is restricted to a range included
in ::

int Arc_Cos_Multiple(INTERVAL &U,INTERVAL &beta,INTERVAL_VECTOR &BETA)This procedure returns the number of possible ranges for and their values in

Jean-Pierre Merlet 2012-12-20