## anonymous one year ago Graph f(x)=2x^2-4, and find the inverse

1. anonymous

@peachpi @vera_ewing

2. anonymous

Did you graph it? and is there a domain restriction for the inverse?

3. anonymous

yes, i graphed it. What does that mean 'domain restriction'?

4. anonymous

is there a restriction on the x values? I ask because f(x) is a parabola and it isn't one-to-one which generally means it doesn't have an inverse without the restriction

5. anonymous

http://fooplot.com/#W3sidHlwZSI6MCwiZXEiOiIyeF4yLTQiLCJjb2xvciI6IiMwMDAwMDAifSx7InR5cGUiOjEwMDB9XQ-- This is the graph, so not that I can see

6. anonymous

You can still solve for an inverse using the usual process, but you can only do it for half the function at a time I think. f(x) = 2x² - 4 y = 2x² - 4 Switch x and y and solve for y x = 2y² - 4 x + 4 = 2y² ½x + 2 = y² $y=\pm \sqrt{\frac{ 1 }{ 2 }x+2}$

7. anonymous

okay:) I understand that :)

8. anonymous

How would you graph the inverse?

9. anonymous

|dw:1439245043828:dw|

10. anonymous

If you have points for f(x) reverse them to get points for the inverse. For example (0,-4) and (1, -2) are on f(x). (-4, 0) and (-2, 1) will be on the inverse

11. anonymous

ohhh! Ok, I get it now:D. So would the inverse be considered a function?

12. anonymous

no it's not a function because it doesn't pass the vertical line test.

13. anonymous

okay, thanks so much:)

14. anonymous

you're welcome