Calculus with Applications (10th Edition)

$4\pi \ln4$
If y=0, then x=-1, x=2, so that a=-1, b=2. The volume is $V=\int^{2}_{-1}\pi(\frac{2}{\sqrt x +2})^{2}dx=4\pi[\ln |x+2|]|^{2}_{-1} =4\pi \ln4$