Let A = {1, 2, 3}, B = {4, 5, 6, 7} and let f = {(1, 4), (2, 5), (3, 6)} be a function from A to B. State whether f is one-one or not.

As, A = {1, 2, 3} and B = {4, 5, 6, 7}

f = {(1, 4), (2, 5), (3, 6)}

Clearly by observing f, we can say that each element of A is related to only 1 element of B.

1→4,2→5 and 3→5.

None of the element of A has two images in set B.

So, by f satisfies the definition of a one-one function

∴ Function f is one-one.