Polar coordinates describe a point using distance and angle instead of x and y. This Woody Calculus lesson explains r and θ, negative radius, graphing, symmetry tests, rose curves, cardioids, limaçons, and the polar area formula.
Parametric equations describe a point moving through the plane. This Woody Calculus lesson explains how \(x=x(t)\) and \(y=y(t)\) create a directed curve, how to compute \(\frac{dy}{dx}\), and how to find horizontal and vertical tangent lines.

