# Systems in the Plane
Why do we care about looking at systems in the plane?
Well - we want to know about equilibrium points and how the system behaves around them.

Recall that equilibrium points are fixed. P = Q = 0
## Some Loose definitions

| Name          | Definition                                                                                           |
| ------------- | ---------------------------------------------------------------------------------------------------- |
| Periodic      | A trajectory loops upon itself                                                                       |
| Stable        | Trajectories converge to a point                                                                     |
| Unstable      | Trajectories diverge from a point                                                                    |
| Linear Center | An equilibrium point that has orbits around it                                                       |
| Limit Cycle   | Happens a lot with nonlinear systems. Trajectories are pulled some target trajectory and stay there. |
|               |                                                                                                      |
# Written Notes
![[LINE Systems in the Plane.png]]
**Documentation**
- [x] ME2016 Week 3 Class ⏳ 2024-09-16 ✅ 2024-09-16