Show that the map d: R" x R" R defined by d(x, y) = ||x-y||/1+||x-y|| ,is a metric, where || || denotes the Euclidean norm on R". (ii) Let d be the above metric. Show that not all closed and bounded subsets of (R", d) are compact. (iii) Does the above phenomenon provide a counterexample to the Heine-Borel theorem? r-yll 1+ ||z-y||