Related Rates (3): Cone Filling or Draining Problem

Related Rates (3): Cone Filling or Draining Problem
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2016-10-18 10:05
This GeoGebra example demonstrates a dynamic cone filling or draining problem, where a slider controls the water level height, and the radius, volume, and rate of change of volume with respect to time are displayed in real time. The core mathematical concept is related rates, a topic in differential calculus, involving implicit differentiation of the cone volume formula V=(1/3)πr²h with respect to time, and the use of similar triangles to relate the radius and height. Construction highlights: the Cone command creates the 3D cone, Polygon and Segment build cross-sections and auxiliary lines, Angle and Distance measure angles and lengths, Translate moves objects, and Textfield provides interactive input. This is suitable for advanced high school or introductory college calculus students, serving as a visual aid for understanding how variables change together in related rates problems, and as a classroom demonstration or self-study tool.

GeoGebra Commands & Parameters

  1. Cone(B, A, h / 2) → a, c, b
  2. Cone(C, A, 20) → d, e, f
  3. Polygon(A, D, E) → poly1, e_1, a_1, d_1
  4. Polygon(A, F, G) → poly2, g_1, a_2, f_1
  5. Segment(D, E) → i
  6. Angle(A, F, G, xOyPlane) → α
  7. Angle(A, D, E, xOyPlane) → β
  8. Distance(D, E) → distanceDE
  9. Distance(F, G) → distanceFG
  10. Segment(I, D) → j
  11. Translate(A, Vector[(-3, 0)]) → A'
  12. Translate(F, (-3, 0)) → F'
  13. Segment(A', F') → k
  14. Distance(A', F') → distanceA'F'
  15. Distance(I, i) → distanceIi
  16. Textfield(h) → InputBox1