How do you find the vertex, focus, directrix, and focal width of the parabola given by the equation x² = 12y?

The equation of the parabola is given as x² = 12y. This is a standard form of a vertical parabola. To analyze the properties of this parabola, we can identify key components:

1. Vertex

The vertex of a parabola in the form x² = 4py is located at the origin (0, 0). For our equation, we can see:

Here, 4p = 12, so we can solve for p:

p = 12/4 = 3

Thus, the vertex is at the point:

(0, 0)

2. Focus

The focus of a parabola is a point that lies on the axis of symmetry of the parabola and is located at a distance of p from the vertex. Since we found that p = 3, the focus will be at:

(0, 3)

3. Directrix

The directrix is a line that is located p units in the opposite direction from the vertex. For our parabola, the directrix will be:

y = -p = -3

4. Focal Width

The focal width (also known as the latus rectum) is the length of the line segment perpendicular to the axis of symmetry that passes through the focus. For a parabola of the form x² = 4py, the focal width is given by:

Focal Width = 4p

Substituting the value of p:

Focal Width = 4 * 3 = 12

Therefore, the focal width of this parabola is 12.

Summary

In conclusion, for the parabola defined by x² = 12y, we have:

  • Vertex: (0, 0)
  • Focus: (0, 3)
  • Directrix: y = -3
  • Focal Width: 12

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