Chapter 6.3, Problem 8E

 Use the region R that is bounded by the graphs of $y=1+\sqrt{x}$, x = 4, and y = 1 to complete the exercises.

 8.    Region R is revolved about the y-axis to form a solid of revolution whose cross sections are washers

  a.    What is the outer radius of a cross section of the solid at a point y in [1, 3]?

  b.    What is the inner radius of a cross section of the solid at a point y in [1, 3]?

  c.    What is the area A(y) of a cross section of the solid at a point y in [1, 3]?

  d.    Write an integral for the volume of the solid.