The Logistic Difference Equation

The logistic difference equation (or logistic map) , a nonlinear first-order recurrence relation, is a time-discrete analogue of the logistic differential equation, . Like its continuous counterpart, it can be used to model the growth or decay of a process, population, or financial instrument.
Depending on the value of the constant , the solution of the difference equation can approach an equilibrium, move periodically through some cycle of values, or behave in a chaotic, unpredictable way.
A visualization of solutions to the logistic difference equation can be obtained using what can be called a "stairstep diagram." A green line intersects back and forth between the graphs of and , beginning at the point . Every intersection of the green line and the red parabola represents a value of . It is easy to see if the solution converges to a single point, oscillates in "square-like" fashion, or is completely unpredictable.


  • [Snapshot]
  • [Snapshot]
  • [Snapshot]
  • [Snapshot]
  • [Snapshot]
  • [Snapshot]


The equilibrium values for determine how or whether the long-term activity of a solution is predictable. If and , then , and the equilibrium solutions are or . Further investigation can be done to show that if , then is an asymptotically stable value. For , solutions converge instead to . For , solutions do not converge to a fixed point, except when exactly for some , in which case for all .
Snapshot 1: the solution converges to a single value
Snapshot 3: where , the solution oscillates with period 2 (a "two-cycle")
For larger values of , the long-term activity is highly chaotic, though there may be certain values of with oscillations of period 4, 8, 16, 32, … . In this chaotic region (), there is a high sensitivity to the value of . Even varying a small amount changes most terms drastically; the solution becomes unpredictable.
Snapshot 5: a solution that is chaotic and ultimately unpredictable; it can, however, be modeled as a simpler, three-cycle approximation
Snapshots 2, 4, and 6: the stairstep diagrams of snapshots 1, 3, and 5, respectively
    • Share:

Embed Interactive Demonstration New!

Just copy and paste this snippet of JavaScript code into your website or blog to put the live Demonstration on your site. More details »

Files require Wolfram CDF Player or Mathematica.

Mathematica »
The #1 tool for creating Demonstrations
and anything technical.
Wolfram|Alpha »
Explore anything with the first
computational knowledge engine.
MathWorld »
The web's most extensive
mathematics resource.
Course Assistant Apps »
An app for every course—
right in the palm of your hand.
Wolfram Blog »
Read our views on math,
science, and technology.
Computable Document Format »
The format that makes Demonstrations
(and any information) easy to share and
interact with.
STEM Initiative »
Programs & resources for
educators, schools & students.
Computerbasedmath.org »
Join the initiative for modernizing
math education.
Step-by-Step Solutions »
Walk through homework problems one step at a time, with hints to help along the way.
Wolfram Problem Generator »
Unlimited random practice problems and answers with built-in step-by-step solutions. Practice online or make a printable study sheet.
Wolfram Language »
Knowledge-based programming for everyone.
Powered by Wolfram Mathematica © 2018 Wolfram Demonstrations Project & Contributors  |  Terms of Use  |  Privacy Policy  |  RSS Give us your feedback
Note: To run this Demonstration you need Mathematica 7+ or the free Mathematica Player 7EX
Download or upgrade to Mathematica Player 7EX
I already have Mathematica Player or Mathematica 7+