A fundamental problem in numerical computation and computational geometry is to determine the sign of arithmetic expressions in radicals. Here we consider the simpler problem of deciding whether m i=1 CiAXi i is zero for given rational numbers Ai, Ci, Xi. It has been known for almost twenty years that this can be decided in polynomial time [2]. In this paper we improve this result by showing membership in uniform TC0 . This requires several significant departures from Bl