Q. Write the equation in vertex form for the parabola with vertex (0,0) and directrix y=8.Simplify any fractions.______
Identify Orientation: Identify the orientation of the parabola based on the directrix.Since the directrix is y=8, the parabola is vertical.
Determine Opening Direction: Determine the direction the parabola opens.The vertex (0,0) is below the directrix y=8, so the parabola opens upward.
Calculate Distance: Calculate the distance between the vertex and the directrix.The distance is ∣0−8∣=8.
Find Value of a: Find the value of a using the distance.The distance is 8, so 8=4a1.Solving for a gives a=4×81=321.
Write Vertex Form Equation: Write the equation in vertex form.Substitute a=321 and the vertex (h,k)=(0,0) into the vertex form equation y=a(x−h)2+k.y=321(x−0)2+0.
Simplify Equation: Simplify the equation. y=321x2.
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