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.