In the metric space (\mathbb R, d)
1) d(x,y) = |{tan}^{ - 1}(x) - {tan}^{ - 1}(y)| ,where x,y are real numbers .
2) d(x,y) = |{tan}^{ - 1}(x) - {tan}^{ - 1}(y)|, where x,y are real numbers .
Show that (\mathbb R, d) w.r.t (1) and (2) are incomplete metric space . Also, what is the...