Question

Algebra 2 help with focal length

Answer 1

you guessed eh ....

Answer 2

yeah i know the steps but not sure how to solve the steps

Answer 3

we have a focus and a directrix, what do these terms mean to you?

Answer 4

focus is a point and the directrix is the line across from it i think thats how you describe it

Answer 5

since we can use a vertex to define the situation, the vertex is the midpoint between the focus and directrix

Answer 6

Thats where i messed up i dont know how to find the midpoint

Answer 7

the points we are looking for all share the same x component in this case soo

f(-5, 5)
<------ v(-5,(5-1)/2)
d(-5,-1)

Answer 8

so we have some form of

y = a(x-h)^2 + k

y = a(x+5)^2 + 2

Answer 9

since the focus is above the directrix, we are open up so a -a is not going to fit ...

Answer 10

wait when you said d(-5,-1) was that the directrix?

Answer 11

that was the point in the directrix that is in line with the focus and vertex

Answer 12

so thats the bottom point in the drawing

Answer 13

the directrix is a line thru y-1; so all points on the directrix are of the form (x,-1)

and since all the points in line fvd have the same x value ... d(-5,-1) is it

yes, thats the point in the picture

Answer 14

**y=-1

Answer 15

what was the vertex again?