The lens equation in optics says that

where d_o is the distance of an object from a thin, spherical lens; d_i is the distance of its image on the other side of the lens; and F is the focal length of the lens (see the accompanying figure). Express F in terms of d_o and d_i, and sketch several level curves of this function (curves of constant focal length).

Transcribed Image Text:

1 do + 1 | || di 1 F