SOLUTION: Find the vertex and directrix for the parabola y + 2 = 1/3 (x+2) ^ 2

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Question 761279: Find the vertex and directrix for the parabola
y + 2 = 1/3 (x+2) ^ 2
Answer by lwsshak3(11628) About Me  (Show Source):
You can put this solution on YOUR website!
Find the vertex and directrix for the parabola
y + 2 = 1/3 (x+2) ^ 2
rewrite equation in basic form: (x-h)^2=4p(y-k), (h,k)=(x,y) coordinates of the vertex.
y%2B2=%281%2F3%29%28x%2B2%29%5E2
3y%2B6%29=%28x%2B2%29%5E2
%28x%2B2%29%5E2=3%28y%2B2%29
This is an equation of a parabola that opens upward.
vertex: (-2,-2)
axis of symmetry: x=-2
4p=3
p=3/4
directrix: y=11/4 (p-units below vertex on the axis of symmetry.
see graph below as a visual check
y= (x^2+4x+4)/3-2
+graph%28+300%2C+300%2C+-10%2C+10%2C+-10%2C+10%2C+%28x%5E2%2B4x%2B4%29%2F3-2%29+