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.

Answer 1

$A=\{1,2,3\}$

$B=\{4,5,6,7\}$

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

Since every element of $A$ has a uniques image.

Hence, $f$ is one-one.