Parametric Equations

Question

x = 9s^2 - 1

y = 1 - 8s^3

find dy/dx in terms of s

find the coordinates of stationary points

Answer 1

dy/dx = (dy/ds)/(dx/ds)
= (-24s^2)/(18s)
= -4s/3

naturally, dy/dx=0 at s = 0

see the graph

http://www.wolframalpha.com/input/?i=plot+x+%3D+9s^2+-+1,++y+%3D+1+-+8s^3