A light is suspended at a height h above the floor (see figure below). The illumination at the point P is inversely proportional to the square of the distance from the point P to the light and directly proportional to the cosine of the angle θ. Let d = 2 ft.

(a) Express the illumination in terms of h only. Use k for the proportionality constant.

(b) How far from the floor should the light be to maximize the illumination at the point P? (in ft)

I am not sure how to approach this problem, I think I am missing something. Attached is a photo of what the problem looks like.