*To*: mathgroup@smc.vnet.net*Subject*: [mg12083] test positive*From*: mam94006@uconnvm.uconn.edu (Manuel A. Morales)*Date*: Sat, 25 Apr 1998 01:30:18 -0400*Organization*: University of Connecticut

I want to test whether a function is always positive for a given set of parameter values. For example, consider the trivial case: f=x*y Is there a way to test whether x*y is positive given that x is greater than 0 and y is less than 0 or both x and y are greater than 0, etc., or better yet to solve for the specific conditions that will yield xy>0. Thanks, Manuel