Parabola Vertex Form: Exploring Parameter Transformations

Parabola Vertex Form: Exploring Parameter Transformations
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2019-06-21 23:27
① This interactive GeoGebra example demonstrates how the parameters a, h, and k in the vertex form of a parabola y = a(x - h)² + k affect its graph, including horizontal/vertical shifts, vertical stretch/compression, and reflection. ② Core mathematical concepts include quadratic functions, vertex form, transformations (translation, scaling, reflection), and the relationship between algebraic equations and geometric graphs. ③ Construction highlights: sliders for a, h, and k are used to define the function f(x) = a*(x - h)^2 + k; the graph is plotted, and auxiliary points such as the vertex, focus, and directrix are constructed (objects like C, D, E, etc.), with a table (tableheading) displaying key coordinates to visualize how parameters affect the geometry. ④ Suitable for middle school to high school students, this example serves as an exploratory tool for learning quadratic function transformations, and as a classroom demonstration aid for teachers to illustrate the geometric meaning of the vertex form.

GeoGebra Commands & Parameters

  1. Numeric k(0.0)
  2. Numeric a(1.0)
  3. Point A(7.5, 5.82)
  4. Point B(7.5, 1.56)
  5. Numeric h(0.0)
  6. f(x) = a * (x - h)^(2) + k
  7. (h, f(h))
  8. (h + 1, f(h + 1))
  9. (h + 2, f(h + 2))
  10. (h + 3, f(h + 3))
  11. (h - 1, f(h - 1))
  12. (h - 2, f(h - 2))
  13. (h - 3, f(h - 3))