|
A
function, f(x), has an inverse function
if f(x) is
one-to-one. |
I know what
you're thinking:
"Oh, yeah! Thanks a
heap, math geek lady. That's very helpful!"
Come on!
You know I'm going to tell you what one-to-one is! Have I
let you down yet?
OK, one-to-one...
There's an easy
way to look at it, then there's a more technical way. (The
technical way will really get us off track, so I'm leaving it
out for now.)
Here's the easy
way:
|
The Horizontal Line Test:
If you can draw a horizontal line so that it hits the graph in
more than one spot, then it is
NOT
one-to-one.
|
Check it out:
| Is |
 |
one-to-one? |
 |
Yep!
| So, |
 |
HAS an |
| inverse
function. |
|
