Question

parabolas :D

Answer 1

Find the standard form of the equation of the parabola with a focus at (0, 6) and a directrix at y = -6.

Answer 2

how do i go about starting this question? .-.

Answer 3

okay so @Zale101 how do you know its going to open up? .-.

Answer 4

(h,k) would be (6,0) right since 0 is halfway between 6 and -6

Answer 5

whats y=-3(x-12)^2+1 in standard form?

Answer 6

so 6-6=1/4*0*(0-6)^2?

Answer 7

that would mean
6-6=1/4*0*(0-6)^2
0=1/4*0*36
0=0 since anything times 0will equal 0.

Answer 8

OMG can someone help me with my question please?

Answer 9

i already told you to go onto wolframalpha

Answer 10

@hartnn @Hero @ganeshie8

Answer 11

how do i figure out that equation for this if it ends up being 0=0 .-.

Answer 12

in ur pic you haven't left any room for drawing directrix :/

Answer 13

yeah i figured that out after but the does that really matter since thats only used to tell you what p is and since halfway between -6 and 6= 0=p? but here

Answer 14

lets see :)
can u draw the directrix line : \(y = -6\) also ?

Answer 15

i thought that the directrix dosent show up in a real graph

Answer 16

okay here it is :
vertex is the midpoint of directrix and Focus :
Vertex = (h, k) = (0, (-6+6)/2) = (0, 0)

Answer 17

p = distance between Focus and vertex = 6-0 = 6

Answer 18

Your equation for parabola is :
\(\large y = \frac{1}{4p}(x-h)^2 +k \)

\(\large y = \frac{1}{4(6)}(x-0)^2 +0\)

\(\large y = \frac{1}{24}x^2\)

Answer 19

we're done^

Answer 20

let me knw if smthng doesnt make sense

Answer 21

no that makes perfect sense c: thank you

Answer 22

yw :) u may double check ur answer wid wolfram :
http://www.wolframalpha.com/input/?i=focus++y+%3D+1%2F24x%5E2

Answer 23

scroll down to the end -
it lists all the properties of that parabola

Answer 24

oh okay c: thank you