Chapter 6.3, Problem 9E

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

 9.    Region R is revolved about the line y = 1 to form a solid of revolution.

  a.    What is the radius of a cross section of the solid at a point x in [0, 4]?

  b.    What is the area A(x) of a cross section of the solid at a point x in [0, 4]?

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