(i) A concave spherical mirror makes an inverted image distinct in size from the object through a factor a > 1. The distance among object and image is d. Determine the focal length of the mirror. (Employ any variable or symbol stated above as required.)
(ii) Assume that the mirror is convex, an upright image is made, and a < 1. Find out the focal length of the mirror. (Employ any variable or symbol stated above as required.)