posted by Anonymous .
The region R is a rectangle with vertices P(a,lna), Q(a,0), S(3,0), and T(3,lna), where 1<a<3.
I found that the expression for the area of the rectangle is f(a) = (ln(a))(3-a).
The area of the rectangle is maximized for some c beween 1 and 3. Write the expression you would need to solve in order to find c.