Question

Derive the equation of the parabola with a focus at (−2, 4) and a directrix of y = 6. Put the equation in standard form.

f(x) = one fourthx2 − x + 4
f(x) = −one fourthx2 − x + 4
f(x) = one fourthx2 − x + 5
f(x) = −one fourthx2 − x + 5

Answer 1

Im getting B

Answer 2

when focus and directrix are given use the deinition of the parabola or locus method.. let (x,y) be the point on the reqd parabola then distance of (x,y) from (-2,4) is sqrt ( (x+2)^2+(y-4)^2 ) and distance of (x,y) from y=6 is (y-6) units so by definition of parabola we have sqrt ( (x+2)^2+(y-4)^2 ) = (y-6) squaring both sides we have (x+2)^2+(y-4)^2 =(y-6)^2 and now just simplify

Answer 3

so yes B

Answer 4

yay :) Can you help with one more?

Answer 5

sure

Answer 6

Derive the equation of the parabola with a focus at (0, -4) and a directrix of y = 4.
(x - x)^2 + (y - 4)^2 = (x - 0)^2 + (y - -4)^2
y^2 -8y + 16 = x^2 + y^2 + 8y + 16
-16 y = x^2
y = - x^2 / 16 (or (-1/16)x^2

Answer 7

so what do u think it is

Answer 8

its B

Answer 9

hope i helped

Answer 10

correct haha, thank you you are a lifesaver!!! :)

Answer 11

your welcome