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Right an equation of a problem given the vertex and the focus

Right an equation of a problem given the vertex and the focus-example-1
User Barremian
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1 Answer

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Given:

A parabola has a vertex (1, -1) and direcrix (x = -5)

The general equation of the parabola will be as follows:


(y-k)^2=\pm4a(x-h)

where the vertex = (h, k)

So, h = 1, k = -1

We will choose the positive sign because the directrix is on the left of the vertex.

the value of (a) is the distance between the vertex and the directrix


a=1-(-5)=6

So, the equation of the parabola will be as follows:


\begin{gathered} (y+1)^2=4*6(x-1) \\ \\ (y+1)^2=24(x-1) \end{gathered}

User Brendan Quinn
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