Let f: R → R be given by f(x) = |x|. This function is:

Let f: R → R be given by f(x) = |x|. This function is:

• A. Bijective
• B. One-one but not onto
• C. Onto but not one-one
• D. Neither one-one nor onto

Answer: D) Neither one-one nor onto

Explanation: f(−2) = f(2) = 2, so it is many-one. Also, negative values in the co-domain do not have any pre-image since |x| ≥ 0. Hence, it is not onto.