The greatest integer function f : R → R given by f(x) = [x], x ∈ R and [x] denotes the greatest integer less than or equal to x is :

one - one onto both one - one and onto neither one - one nor onto

neither one - one nor onto

f(x) = [x]   e.g  for x = 2.1, 2.3 f(2.1) = [2.1] = 2 f(2.3) = [2.3] = 2 for R → R ⇒ its not one one e.g for f(x) = Non integral values  x → doesn't exist (not onto)