Two curves are orthogonal if their tangent lines are perpendicular at each point of intersection. Show that

Question:

Two curves are orthogonal if their tangent lines are perpendicular at each point of intersection. Show that the given families of curves are orthogonal trajectories of each other; that is, every curve in one family is orthogonal to every curve in the other family. Sketch both families of curves on the same axes.
y = ax3, x2 + 3y2 = b