Question

Write the equation of the parabola below:
Directrix: x=3/4
Focus at : (5/4, -3)

Answer 1

@superdavesuper ? Help? ;/

Answer 2

hi @Maddy1251 :) oh i know tis one lol

look at the plot here: http://www.mathwords.com/d/directrix_parabola.htm

note the vertex...where is it in ur plot?

Answer 3

@superdavesuper the vertex of that parabola is (3,-2)

Answer 4

I don't know where it is at in my plot :P

Answer 5

good good now check out the eqn for parabola here:

http://www.mathwords.com/p/parabola.htm

w vertex at (h,k)....

Answer 6

@superdavesuper thats the same graph as before, but, Is it saying that the focus is the same distance away from the vertex just like the directrix is the same difference from the vertex?

Answer 7

Which would then be (1,-3)?

Answer 8

correct - the vertex is at the mid-pt between focus n directix :)

Answer 9

Okay :) and the parabola I have listed is a horizontal one. @superdavesuper

Answer 10

@Maddy1251 oh u are right....well just flip x n y in the vertix form then :)

Answer 11

I did! I think I got it thank you so much :)

Answer 12

welcome :)