Question

Find the equation of the parabola with its focus at (5,0) and it’s directrix y=2

Answer 1

Answer:

Option A

Step-by-step explanation:

From the question given in the picture attached,

Directrix of the parabola → y = 2

Focus of the parabola → (-5, 0)

Since, focus is below the directrix, parabola will open open downwards.

Equation of the parabola will be in the form of,

y - k = -4p(x - h)²

Here, (h, k) is the vertex of the parabola

p = Distance between vertex and focus or distance between vertex and directrix

Since, distance between vertex and focus = Distance between vertex and directrix

Therefore, vertex of the parabola → (-5, 1)

Now distance (p) between vertex (-5, 0) and focus (-5, 1) = 1 unit

By substituting these values in the equation,

y - 1 = -4(1)[x - (-5)]²

y - 1 = -4(x + 5)²

y = -4(x + 5)² + 1

Option A will be the answer.