The semi-vertical angle of the cone of the maximum volume and of given slant height is

\(\tan^{-1}\sqrt{3}\) \(\tan^{-1}(\sqrt{2})\) \(\tan^{-1}(2)\) None of the above

\(\tan^{-1}(\sqrt{2})\)

Volume \(=\frac{1}{3}\pi r^2 h\)