HELP the equation for the directrix of this parabola is x=-1. x=1/4y^2 true or false

Question

anonymous · Answer

not true

anonymous · Answer

$$\frac{1}{4}y^2= x$$$$y^2=1(4x)$$$$4p=1$$$$p=\frac{1}{4}$$focus = 1/4
dirextrix: x= -1/4
not x=-1

anonymous · Answer

I see 4p = 4 -> p = 1

anonymous · Answer

no

anonymous · Answer

if
4(x+1) 
than 4p =4
          p=1
then directrix x=-1

anonymous · Answer

I'm confused, since I always remember y^2 = 4px

anonymous · Answer

yes but y^2 = 4x
than 4x= 1(4x)
4p =1
p=1/4

anonymous · Answer

Thanks, Nancy! I'm looking it up now.

anonymous · Answer

what is the equation of the parabola, in vertex form, with focus at (2,-4) and directrix y=-6

phi · Answer

phi · Answer

Click on properties in the box labeled "geometric figure"

anonymous · Answer

anonymous · Answer

anonymous · Answer

I check several other sources but it's not as the way the calculated, also the text book!!!

anonymous · Answer

help what is the equation of the parabola, in vertex form, with focus at (2,-4) and directrix y=-6

anonymous · Answer

Focus F (h, k+p) = (2, -4) 
Directrix y = k -p = -6
-> h = 2, k = 1, p = -5
=> (x -2)^2 = 4(-5) ( y -1)
Thus (x -2)^2 = -20 ( y -1)

anonymous · Answer

Rini, I'm going to fix the last one you asked me.