Analysis and calculus · Maths EE idea · Ambitious

The fastest slide: why a cycloid?

A research question to start from

Why is the cycloid the curve of fastest descent between two points, and how much faster is it than a straight line or a circular arc?

A starting point, not your question: change the case, the comparison or the limit until it is yours. The research-question builder helps you check it.

Why it works as a maths EE

A famous optimisation with a derivation and a comparison you can compute exactly.

Mathematics you would need

  • Parametric curves
  • Integrals for time of travel
  • Energy conservation
  • Introduction to the calculus of variations

Much of this goes beyond the DP course. That is expected in a maths EE, but you must understand and explain everything you use.

One possible line of attack

  1. Set up the time integral for a general curve.
  2. Derive the cycloid (citing and explaining the Euler–Lagrange step).
  3. Compute descent times for several curves and compare.

Scope and difficulty

Ambitious. Ambitious; the calculus of variations must be explained, not just quoted.

Pitfalls

  • Physics essay with thin mathematics.
  • Times compared without exact integrals.

Where to start reading

Search a library catalogue or a university's open lecture notes for: brachistochrone derivation cycloid; time of descent comparison. Prefer textbooks, lecture notes and journal articles to a single website, and cite everything you use (how to reference a maths EE).

Make it your EE

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