Mathematics

Problem

A solid has base region bounded by the graph of

y=\sqrt{x}

and the

x

-axis for

0\le x\le 9

. Cross sections perpendicular to the

x

-axis are squares. Which of the following definite integrals represents the volume

V

of the solid? a)

\displaystyle \int_{0}^{3} y^{2}\,dy

\displaystyle \int_{0}^{9} \sqrt{x}\,dx

\displaystyle \int_{0}^{9} x\,dx

\displaystyle 2\int_{0}^{9} x\,dx