## Babynini one year ago Equation for lower half of parabola.

1. Babynini

Find an eq for the lower half of the parabola, without restriction. (y-5)^2 = 4x-2

2. hwyl

it says for the lower half

3. zepdrix

It's a parabola opening to the RIGHT, ya? So if you drew it, you would see that it fails the vertical line test. We want to show that either branch of the parabola IS a function. So we'll end up with y=(plus/minus) squareroot(x stuff) and to get the LOWER Half of the parabola, we want the negative of that root.

4. zepdrix

Do you understand how to get it into the form y=stuff from what they've given you? :)

5. Babynini

em i'm trying but i'm getting it wrong.

6. zepdrix

You ... you and your ways miriam -_- ok let's see where we're going wrong,$\Large\rm (y-5)^2 = 4x-2$

7. zepdrix

square root as first step, ya?

8. zepdrix

$\Large\rm y-5=\pm\sqrt{4x-2}$Add some 5 business in there,$\Large\rm y=\pm\sqrt{4x-2}+5$

9. zepdrix

We want the lower branch, ya? So we only want the negative root,$\Large\rm y=-\sqrt{4x-2}+5$

10. Babynini

I was simplifying first and that was making it come out wrong

11. zepdrix

|dw:1433476275143:dw|

12. zepdrix

woops i buried the wrong solution in the picture -_- hehe

13. zepdrix

Oh simplifying? i see

14. Babynini

aww lightbulbs stil haha

15. Babynini

it's ok, it's fabulous ;D

16. zepdrix

heh :3