A patient is going to be prescribed bifocals which will be 2.50 cm from the eye. The prescribed powers (in diopters) for the bifocals are +1.60 and -0.40, and these bifocals give the patient normal vision.

Question

A patient is going to be prescribed bifocals which will be 2.50 cm from the eye. The prescribed powers (in diopters) for the bifocals are +1.60 and -0.40, and these bifocals give the patient normal vision.
(a) Without the bifocals, what is the patient's near point?
  cm
(b) Without the bifocals, what is the patient's far point?