Consider the curve x=3cost,y=2sint for 0≤t≤2π.
a. (i) Find all parameter values t for which the tangent to the curve is horizontal.
b. (ii) Find all parameter values t for which the tangent to the curve is vertical.
c. (iii) Determine the corresponding Cartesian coordinates of every point with a horizontal or vertical tangent obtained in parts (i) and (ii).