14.6 Review of the course

The course has followed one thread: from the explicit solution of special equations to the qualitative understanding of general ones.

Question

Main tools (sections)

Does a solution exist, is it unique?

Picard–Lindelöf, Peano, Gronwall (2); maximal solutions, blow-up (3)

How does it depend on the data?

Continuous dependence (2); variational equation (3)

What do linear systems do?

Fundamental matrices, Liouville (4); \(e^{At}\), Jordan form (5); Laplace (6)

Periodic coefficients?

Floquet multipliers, Hill, Mathieu (7)

Variable coefficients?

Frobenius, special functions (8); Sturm–Liouville (9)

Is an equilibrium stable?

Linearisation, Hartman–Grobman (10); Lyapunov, LaSalle (11)

Are there oscillations?

Poincaré–Bendixson, Dulac, Liénard (12); averaging (14)

What happens as parameters vary?

Saddle-node, pitchfork, Hopf; chaos (13)

How do we compute it?

Perturbation methods; Runge–Kutta, stiffness (14)

Questions on this section

Stuck on something here? Ask below and it stays attached to this topic.