Math — Parametric & Implicit Differentiation

\frac{dy}{dx} = \frac{dy/dt}{dx/dt}

\frac{d^2y}{dx^2} = \frac{d}{dt}\!\left(\frac{dy}{dx}\right)\Big/\frac{dx}{dt}

\frac{d}{dx}F(x,y) = 0

x = r\cos t,\quad y = r\sin t