What is the equation of a parabola if the vertex

Question

. What is the equation of a parabola if the vertex is (1, 4) and the directrix is located at y = 3

Answer 1

Hello!

These are some steps for you to get started:

your directix is perdendicular to your axis of symmetry, so you know if your line is y = 3 your parabola will open up or down where your axis of symmetry is perpendicular to the x axis. do you remember your axis of symmetry?

So use this formula

(x-h)^2 = 4p(y-k) and your directix is (y, k-p).

Since your vertex is(1,4) that is (h,k)

so your h = 1 and your k = 4

can you now plug h and k and your point (0,3) where x = 0 and y = 3 into the formula to find your p?

These are some steps to get you started>

Let me know if you have any more questions, there are a lot of concepts in here!

Best,

Julie

www.wyzant.com/tutors/missjulie