/* fi_lib: interval library version 1.2, for copyright see fi_lib.h */ # include "fi_lib.h" interval j_acos(interval x) { interval res; if (x.INF == x.SUP) { res.INF = q_acos(x.INF); res.SUP = res.INF * q_ccsp; res.INF *= q_ccsm; } else { res.INF = q_acos(x.SUP) * q_ccsm; res.SUP = q_acos(x.INF) * q_ccsp; } return res; }