125k views
4 votes
The vertex of a parabola is (3, 0), and the directrix is x = 0.25. What is the equation of the parabola?

a) y = (x - 3)²
b) y = -(x - 3)²
c) y = (x - 3)² + 4
d) y = -(x - 3)² - 4

1 Answer

5 votes

Final answer:

The equation of the parabola with vertex (3, 0) and directrix x = 0.25 is not represented by any of the given options. The correct form is derived from (y - 0)² = 11(x - 3) for a parabola that opens to the right, which simplifies to y = √[11(x - 3)].

Step-by-step explanation:

The question involves finding the equation of a parabola given the vertex and the directrix. We know that if the directrix is a vertical line (like x = constant), the parabola must open horizontally. Since the vertex is at (3, 0) and the directrix is x = 0.25, the parabola opens to the right, away from the directrix.

The general equation for a horizontally opening parabola with vertex (h, k) is (y - k)² = 4p(x - h), where p is the distance from the vertex to the directrix. Here, since the vertex is (3, 0) and the directrix is x = 0.25, p = 3 - 0.25 = 2.75. Plugging these values into the equation, we get (y - 0)² = 4(2.75)(x - 3), which simplifies to y² = 11(x - 3). This equation needs to be in y = ax² + bx + c form, so rewrite it as y = √[11(x - 3)] because we are dealing with the top half of the parabola.

Therefore, none of the options a), b), c), or d) are correct for the given vertex and directrix.

User Divakar Gujjala
by
7.8k points

No related questions found