SOLUTION: A vertical parabola has a vertex at (-3,-2) and passes through the point (-1,7). Find the equation of the parabola, the equation of the directrix, and the coordinates of the focus

Algebra ->  Quadratic-relations-and-conic-sections -> SOLUTION: A vertical parabola has a vertex at (-3,-2) and passes through the point (-1,7). Find the equation of the parabola, the equation of the directrix, and the coordinates of the focus       Log On


   



Question 817916: A vertical parabola has a vertex at (-3,-2) and passes through the point (-1,7). Find the equation of the parabola, the equation of the directrix, and the coordinates of the focus point.
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 
Hi,
the vertex form of a Parabola opening up(a>0) or down(a<0), y=a%28x-h%29%5E2+%2Bk
where(h,k) is the vertex and x = h is the Line of Symmetry
The standard form is %28x+-h%29%5E2+=+4p%28y+-k%29, where the focus is (h,k + p)
A vertical parabola has a vertex at (-3,-2)
y = a(x+3)^2-2 |passes through the point (-1,7).
7 = a(2^2)-2
9/4 = a
y+=+%289%2F4%29%28x%2B3%29%5E2-2
%284%2F9%29%28y%2B2%29+=+%28+x%2B3%29%5E2+ 4p = 4/9, p = 1/9 F(3, -17/9)