Question

Is the graph of the function shown in the graph below one-to-one? Why?

Answer 1

NOTE :

Horizontal line test :

If a horizontal line intersects the graph of a function at only one point, then function is one-to-one.

Observe the graph, any horizontal line can intersects the graph at two distinct points.

So, f  is not a one- to-one function.

Answer 2

It's simple. draw a horizontal line on the graph. If the line intersects a function's graph more than once, then the function is not one-to-one.

Since the line crossing the function graph more than once, its not one-one-to function.