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A parabola with a vertex at (0,0) has a directrix that crosses the negative part of the y-axis. Which could be the equation of the parabola? x2 = –4y x2 = 4y y2 = 4x y2 = –4x

User GoodViber
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2 Answers

2 votes

Answer:

x² = 4·y

Option B

Step-by-step explanation:

Trust! :)

User Danielbeard
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6 votes

Answer:

The option that could be equation of the parabola is;

x² = 4·y

Step-by-step explanation:

The location of the vertex of the parabola = (0, 0)

The location of the directrix of the parabola = The negative part of the y-axis

Given that the directrix crosses the y-axis, the directrix can be taken as being parallel to the y-axis, and the equation of the directrix presented as follows;

y = k - p

Therefore, the general equation of the parabola is of the following form;

(x - h)² = 4·p·(y - k)

Given that the directrix, y = k - p is negative, and the vertex, (h, k) = (0, 0) therefore;

h = 0, k = 0

y = k - p = 0 - p = -p

y = -p (negative), therefore, 'p' = Positive > 0

The equation of the parabola becomes;

(x - 0)² = 4·p·(y - 0)

∴ x² = 4·p·y

Where p = 1 (assumption), we get the possible equation of the parabola presented as follows;

x² = 4·y.

User Mandubian
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