Answer
a.) $\displaystyle{V=2\pi\int_{0}^{\pi}4\sqrt{\sin y}-y\sqrt{\sin y}\ dy}\\ $
b.) $\displaystyle{V=36.57476}$
Work Step by Step
a.)
$\displaystyle{V=\int_{0}^{\pi}\left(2\pi\left(4-y\right)\right)\left(\sqrt{\sin y}\right)\ dy}\\
\displaystyle{V=2\pi\int_{0}^{\pi}4\sqrt{\sin y}-y\sqrt{\sin y}\ dy}\\ $
b.)
$\displaystyle{V=36.57476}$
