Question

write equation for parabola
focus (2,1) opens right, contains (8,-7)

Answer 1

@jim_thompson5910

Answer 2

k i find the distance between F and point given which is 10 then what?

Answer 3

@jim_thompson5910

Answer 4

one sec

Answer 5

ok

Answer 6

ok here's a good picture that describes what a parabola truly is

http://www.mathwords.com/f/focus_parabola.htm

Answer 7

it's basically a set of points that if you pick any point on the parabola P, then the distance from P to F (focus) will be the same as the distance from P to the directrix

Answer 8

you found the distance from the focus to the point to be 10 units

Answer 9

so this point is 10 units from the directrix

Answer 10

so where is the directrix? what's the equation?

Answer 11

hold on

Answer 12

ok

Answer 13

i will move left 10 points?

Answer 14

confused

Answer 15

good

Answer 16

about what

Answer 17

can we work throught this question?

Answer 18

if x = 8 and you go 10 units to the left, then you end up at x = ??

Answer 19

-2?

Answer 20

so x = -2 is the directrix

Answer 21

the vertex will be the point (0,1) since that's the midpoint of the segment that connects the focus and it's perpendicular to the directrix

Answer 22

hmm can u plz plz plz draw that?

Answer 23

sry it's hard to draw a parabola on here

Answer 24

it is okay k next step

Answer 25

you know the vertex is (0,1), so h = 0, k = 1

Answer 26

yes

Answer 27

the focal distance is p = 2 since the vertex is 2 units way from the directrix

Answer 28

ok

Answer 29

@jim_thompson5910 that's it?

Answer 30

no you would use the formulas given on that page i sent you

Answer 31

to find the equation

Answer 32

okay i will do that!

Answer 33

ok great

Answer 34

(y-1)^2=8(x-0)

Answer 35

perfect, you can also write that as (y-1)^2 = 8x

Answer 36

okay thanks!

Answer 37

yw