Solution  f is not one-one, as f (1) = f (2) = 1 But f is onto, as given any y ∈ N, y ≠ 1,
we can choose x as y + 1 such that f (y + 1) = y + 1 – 1 = y Also for 1 ∈ N, we
have f (1) = 1 Example 11  Show that the function f : R → R,
defined as f (x) = x2, is neither one-one nor onto