A person is to be fitted with bifocals She can see clearly w

A person is to be fitted with bifocals. She can see clearly when the object is between 26.0cm and 1.2m from the eye. Since the upper portion of the bifocals should be designed to enable her to see distant objects clearly, what is the power they should have (in diopters)? The lower portion of the bifocals in the question above should enable her to see objects comfortably at 25.0cm. What power should they have (in diopters)?

Solution

f(x) = 3sqrt(x) and g(x) =6x

a).

(fog)(4) = f[g(4)]

=f[6*4]

=f(24)

= 3sqrt(24)

=3sqrt(8*3)

=6 sqrt(6)