Question: if x=a cos^3 t and y=a sin^3 t, where a is a constant , find dy/dx in term of t
x = a.cos^3(t)
x' = -3a.sin(t).cos^2(t)
y = a.sin^3(t)
y' = 3a.cos(t).sin^2(t)
dy/dx = y'/x' = {3a.cos(t).sin^2(t)}/{-3a.sin(t).cos^2(t)} = -tan(t)
dy/dx = -tan(t)