Question

Let A = {1, 2, 3}, B = {2, 3, 4}, then which of the following is a function from A to B ?

• A. {(1, 2), (1, 3), (2, 3), (3, 3)}
• B. {(1, 3), (2, 4)}
• C. {(1, 3), (2, 2), (3, 3)}
• D. {(1, 2), (2, 3), (3, 2), (3, 4)}

Answer 1

The correct option is C

{(1, 3), (2, 2), (3, 3)}

{(1, 3), (2, 2), (3, 3)}
we have
R = {(1, 3), (2, 2), (3, 3)}
We observe that each element of the given set has appeared as first component in one and only one ordered pair of R.
So, R = {(1, 3), (2, 2), (3, 3)} is a function.