Phase Plane Analysis is a graphical method used to study the behavior of dynamical systems by plotting their state variables against each other. This technique helps visualize how the system evolves over time, revealing important features such as equilibrium points, stability, and periodic orbits. It is commonly applied in fields like control theory, mechanical systems, and biological modeling. In a phase plane, each point represents a unique state of the system, while trajectories show how the system transitions between states. By analyzing these trajectories, researchers can gain insights into the system's long-term behavior and identify conditions for stability or instability, making it a valuable tool in mathematics and engineering.