SOLUTION: Using the given equations of parabolas, find the focus, the directrix and the equation of the axis of symmetry. 1.) y=1/28x^2 2.) x=1/8y^2

The parabola  has vertex (0,0), focus (0,p), 

equation of directrix y=-p,

equation of axis of symmetry x=0 (the y-axis)

1.) 

Multiply through by 28



Turn backwards:



so comparing to 






So it has vertex (0,0), focus (0,p) = (0,7), 

equation of directrix y=-p, or y=-7

equation of axis of symmetry x=0 (the y-axis)

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The parabola  has vertex (0,0), focus (0,p), 

equation of directrix x=-p,

equation of axis of symmetry y=0 (the x-axis)


2.) 

Multiply through by 8



Turn backwards:



Compare to 






So it has vertex (0,0), focus (p,0) = (2,0), 

equation of directrix x=-p, or x=-2

equation of axis of symmetry y=0 (the x-axis)

Edwin