Consider the parametric curve x=t3−3t and y=t4−4t2+5.
a. (i) Show that dxdy=3t2−34t3−8t.
b. (ii) Determine all real values of t for which the tangent to the curve is horizontal.
c. (iii) Determine all real values of t for which the tangent to the curve is vertical.
d. (iv) For each value of t obtained in parts (ii) and (iii), find the corresponding coordinates of the points on the curve.