Show that the minimum distance between an object and its image, formed by a thin lens, is 4f. In what situation does this minimum occur? b) A thin diverging lens and a concave mirror have equal focal lengths, an object is placed at a distance 3f/2 to the left of the lens, while the mirror is at a distance 3f on the other side of the lens. Describe the final image of this system after two refractions including a ray diagram.