Prove that the set x = [1, 2]u[3, 4] cr is not convex.

2.4 functions 41 (c) the intersection of two closed sets is closed (d) the cortacion product of two closed sets is closed (e) the intersection of two convex sets is convex (1) (from definitions 2.15, 2.16, and 2.17) a closed set contains its boundary points (g) the union and intersection of two bounded sets is bounded for e = 0.1 and € = 10, describe the e-neighborhoods: (a) ) (b) ,1) (c) ,1,-1) prove that the set