The greatest integer function f: R → R given by f(x) = [x] is:

The greatest integer function f: R → R given by f(x) = [x] is:

• A. One-one and onto
• 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(1.2) = 1 and f(1.8) = 1, so it is many-one. The range of f is Z (set of integers), which is not equal to the co-domain R. Thus, it is not onto.