Applied mathematics and modelling · Maths EE idea · Solid

From order to chaos in the logistic map

A research question to start from

How does the long-term behaviour of xₙ₊₁ = r xₙ(1 − xₙ) change with r, and where do the first period doublings occur?

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

Exact stability calculations for fixed points and 2-cycles, then a controlled look at chaos.

Mathematics you would need

  • Iteration and fixed points
  • Stability using derivatives
  • Period-2 cycles
  • Bifurcation diagrams

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. Find fixed points and their stability.
  2. Find the 2-cycle and where it becomes unstable.
  3. Explore further doublings numerically and discuss.

Scope and difficulty

Solid. Solid.

Pitfalls

  • Chaos pictures with no calculations.
  • Undefined claims of 'chaos'.

Where to start reading

Search a library catalogue or a university's open lecture notes for: logistic map period doubling stability derivative; 2-cycle logistic map. 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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