Mathematics

Problem

Region

R

is bounded by the curve

y=\sqrt{x}

and the lines

x=1

and

x=3

. When

R

is revolved about the

y

-axis, a student plans to integrate with respect to

x

. Which of the following expressions represents the outer radius of a typical washer in terms of

x

? a)

x

3-x

3

\sqrt{x}