Matching Parabola to Locus of Midpoint of Focal Chord

Matching Parabola to Locus of Midpoint of Focal Chord
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2014-01-21 17:30
This example demonstrates the locus of the midpoint of a focal chord in a parabola. By adjusting the parabola's parameters, users can observe how the midpoint M traces a curve and verify its relationship with the original parabola. Core mathematical concepts include the definition of a parabola, focus, directrix, focal chord, and the derivation of the midpoint locus. Construction details: using GeoGebra commands such as Point, Line, Intersect, Midpoint, and Segment, the parabola c, focus A, and points B, C, D on the focal chord are constructed, with M as the midpoint. Sliders a, b, h, k control the parabola's equation, and text objects display dynamic values. Suitable for high school or college analytic geometry courses, this interactive tool helps students visualize the algebraic form of the midpoint locus and supports inquiry-based learning.

GeoGebra Commands & Parameters

  1. Point(yAxis) → A
  2. Point(c) → B
  3. Line(B, A) → a_1
  4. Intersect(c, a_1) → C, D
  5. Midpoint(C, D) → M
  6. Segment(B, D) → b

AI Drawing Prompt Reference

Draw a parabola with adjustable parameters. Place a focus on its axis of symmetry. Choose a point on the parabola and connect it to the focus with a line; this line intersects the parabola at another point. Find the midpoint of these two intersection points and trace its path as the parabola changes. Also draw a segment between the first chosen point and the second intersection to show the focal chord. Observe how the midpoint's locus relates to the original parabola.
The prompt above was compiled from the original drawing commands and is for reference only.