This lecture discusses the relationship between hyperbolic functions and trigonometric functions, focusing on the circle and hyperbola. It explains how points on the unit circle correspond to cos(t) and sin(t), while points on the hyperbola x² - y² = 1 correspond to cosh(t) and sinh(t). The lecture also demonstrates how to find t values for given points on the hyperbola using examples. Additionally, it covers the properties of points on the hyperbola and their relation to the hyperbolic functions cosh(t) and sinh(t).