Given two functions x = at^3 and y = 4a, find dy/dx

Solution: Parametric Differentiation with utilisation of Chain Rule.
By the chain rule: dy/dx = dy/dt * dt/dx
Note: dt/dx = 1 / (dx/dt)
So dy/dt = 0, dx/dt = 3at^2
So dy/dx = 0 * 1/(3at^2) and hence dy/dx = 0.