1. The document discusses parametric equations, which express the variables x and y in terms of a third variable called a parameter. Common parameters include s, t, and θ. 2. It provides examples of converting parametric equations to Cartesian form by eliminating the parameter through substitution or trigonometric identities. This includes the equations of circles, parabolas, ellipses, and hyperbolas. 3. Key parametric equations that define common curves are identified, along with the curves they represent. Methods for sketching curves from their parametric equations are also outlined.