If $x = 3\tan t$ and $y = 3\sec t$, then the value of $\frac{d^2y}{dx^2}$ at $t = \frac{\pi}{4}$, is: (1) $\frac{1}{6}$ (2) $\frac{1}{6\sqrt{2}}$ (3) $\frac{1}{3\sqrt{2}}$ (4) $\frac{3}{2\sqrt{2}}$
If $x = 3\tan t$ and $y = 3\sec t$, then the value of $\frac{d^2y}{dx^2}$ at $t = \frac{\pi}{4}$, is:\\
(1) $\frac{1}{6}$\\
(2) $\frac{1}{6\sqrt{2}}$\\
(3) $\frac{1}{3\sqrt{2}}$\\
(4) $\frac{3}{2\sqrt{2}}$