Question

Explain in more detail about one to one and onto function?

Answer 1

For one to one function each element in the domain is mapped on to an one and only one element in the co-domain.

The could be some elements in the co-domain that are not being used.

For a function to be one to one, then for

$f(x) = f(y)$
if and only if

$x = y$

For an onto function all the elements in the co-domain must be used up.

In order words, the $co-domain=Range$

The condition is
$f(x) \rightarrow \: y$
Meaning each $OBJECTshould have an IMAGE$