Is the above relation a function?

[aisha]

X X X
X
X
X
X
X

X X X

These are the points on my graph. The question says is the above relation a function? I think this is a function, but I don't know how to justify my answer.

Also it says is the inverse of this a function? How do I know? I am thinking no because f(x) is already a function so it won't pass the horizontal line test, therefore the inverse will not be a function.?? Help me out please.

 

[phreak]

The Vertical Line test. If you can draw a vertical line through any point in the graph and it goes through two points, it's not a function. Otherwise, it IS a function. From your graph, it looks like it isn't a function since drawing a vertical line would result in more than one y result.

Also, judging from your graph, when you rotate it 90 degrees and use the vertical line test, it should also fail, meaning that both the function and its inverse aren't functions.

 

[aisha]

The Vertical Line test. If you can draw a vertical line through any point in the graph and it goes through two points, it's not a function. Otherwise, it IS a function. From your graph, it looks like it isn't a function since drawing a vertical line would result in more than one y result.

Also, judging from your graph, when you rotate it 90 degrees and use the vertical line test, it should also fail, meaning that both the function and its inverse aren't functions.

Thanks I got it.