Let A = {1, 2, 3}, B = {4, 5, 6, 7} and let f = {(1, 4), (2, 5), (3, 6)}
Question:

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 $B$. Show that $f$ is one-one.

Solution:

It is given that $A=\{1,2,3\}, B=\{4,5,6,7\}$.

$f: A \rightarrow B$ is defined as $f=\{(1,4),(2,5),(3,6)\}$.

$\therefore f(1)=4, f(2)=5, f(3)=6$

It is seen that the images of distinct elements of A under f are distinct.

Hence, function f is one-one.