Question

Derive the equation of the parabola with a focus at (−7, 5) and a directrix of y = −11.

f(x) = one thirty second (x + 7)2 − 3

f(x) = −one thirty second (x + 7)2 − 3

f(x) = −one thirty second (x − 7)2 − 3

f(x) = one thirty second (x − 7)2 − 3

Answer 1

@amoodarya

Answer 2

@amistre64 @norasparkle4 @doggy @xxfaliottaxx @m@Kamille @itsloverboy @UmarsBack @undeadknight26 @elle_girl_0201 @PixieDust1 @Preetha

Answer 3

cam somebody help me please

Answer 4

is the focus above or below the directrix? and what would that tell us?

Answer 5

i have no idea

Answer 6

i dont really know how to work this type of equation out i suck at math big time:(

Answer 7

the focus is located at y=?
the directrix is located at y=?

Answer 8

ummmmm........

Answer 9

the focus is -7,5 and y is -11

Answer 10

right

Answer 11

yes, but we are only concerned at the moment of the y values to see in what direction we want the parabola to open up

if the focus y value is bigger than the directrix value, we are up

if the focus y value is smaller than the directrix value, we are down

do you recall what part of a parabola equation tells us if it opens up or down?

Answer 12

no i really dont sorry

Answer 13

if the first part is positive, we are up; if it is negatvie we are down