Question 768365:        
    
Identify the vertex, focus, and directrix of the graph
 
y=1/20(x-3)^2-3
 
Is the following correct:
 
Vertex (3,-3) 
Focus (3,2) 
Directix = -8 
    
  
    
  
    
  
  
 
 Answer by lwsshak3(11628)      (Show Source): 
You can  put this solution on YOUR website! Identify the vertex, focus, and directrix of the graph 
y=1/20(x-3)^2-3 
(y+3)=(x-3)^2/20 
(x-3)^2=20(y+3) 
This is an equation of a parabola that opens upward. 
Its basic form: (x-h)^2=4p(y-k), (h.k)=(x,y) coordinates of the vertex 
For given parabola: 
vertex: (3,-3) 
axis of symmetry: x=3 
4p=20 
p=5 
focus: (3,2) (p-units above vertex on the axis of symmetry) 
directrix: y=-8 (p-units below vertex on the axis of symmetry) 
congratulations! you got all the answers correct 
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