Math 130B: Ordinary Differential Equations, part II.


Homework solutions.

Below are links to homework solutions; the topics of the problems are indicated.
  • Homework 1. Find null-clines; find stationary points. Plot phase-portraits and bifurcation diagram.
  • Homework 2. Stability of stationary points. Basins of attraction and Lyapunov-functions. Gradient systems.
  • Homework 3. Hamiltonian systems; gradient systems. Some calculus.
  • Homework 4. Systems in polar coordinates. Alpha- and omega- limit sets. Limit cycles. Lyapunov-functions.
  • Homework 5. More alpha- and omega-limit sets. Local sections. Periodic orbits. Linearised systems.
  • Homework 6. Period of orbits. Predator-prey systems.
  • Homework 7. More predator-prey system. Also generalised competing-species systems. The Bendixson-Dulac criterion.
  • Homework 8. More null-clines and phase-portraits. Convert to polars.
  • Homework 9.. Show that this system does not exhibit chaos. Note: These are not quite done. And not entirely correct either.