Curiosities · Foundation · 5 min

The logistic map

One simple recurrence can settle, oscillate, or become strikingly irregular.

WHAT HAPPENS IF…Compare r=2.8 with r=3.4. Does the orbit approach one point?
Interactive exploration
Preparing your experiment…

Connect the picture to the ideaxn+1=rxn(1−xn)x_{n+1}=r x_n(1-x_n)

Starting with x₀, move vertically to the parabola y=r x(1−x), then horizontally to y=x to turn the output into the next input. The fixed points solve x=r x(1−x): x=0 and, when r≠0, x=1−1/r. The latter has derivative 2−r, so it is attracting when 1<r<3.

A detail that matters

A complicated-looking finite orbit does not by itself establish chaos. The displayed model uses floating-point arithmetic.

Keep the connection going

One idea leads to another.

More curiosities ↗