Derive the equation of the parabola with a focus at (0, -4) and a directrix of y = 4.

Question

undeadknight26 · Answer

I got f(x) = 16x^2

anonymous · Answer

Still using that picture, eh?

anonymous · Answer

Pretty embarrassing tbh.

undeadknight26 · Answer

Ayeeeee XD

undeadknight26 · Answer

Its fine by me lel

haseeb96 · Answer

for equation of Parabola 
the focus is given that is 
(0,-4)
and the directrix y=4

haseeb96 · Answer

here a =-4 
and this parabola is along y axis 
so the equation would be in this form 
x=4ay 
now just put a =-4 in the above equation and get the answer

haseeb96 · Answer

*x^2 =4ay

haseeb96 · Answer

x^2 = 4(-4) y 
 x^2 =-16 y 
is the equation of parabola

undeadknight26 · Answer

sooo:
x^2 = 4(-4)y?
x^2 = -16y?
should i now invert it so its:
y = -16x^2?

haseeb96 · Answer

no when  focus =(a,0) is on this condition then 
we will use this equation parabola  
that is 
y^2=4ax 
and when focus =(0,a) is on this condition then
we will use this equation parabola  
that is 
x^2=4ay 
okay 
i think u got it

undeadknight26 · Answer

Can you help me wif one more mate?