$\"\"$

The function is $\"\"$ .

Graph of the function $\"\"$ :

$\"\"$

Observe the graph:

$\"\"$ .

$\"\"$ is not one-to-one because many different $\"\"$ -values yields the same $\"\"$ -value.

$\"\"$

The function is not one-to-one, because many different $\"\"$ -values yield the same $\"\"$ -value.