If $ A = \left[\begin{array}{cc} 3 & 1 \\2 & 4 \end{array}\right] $, then the determinant of the adjoint of $ A^2 $ is:
Evaluate the following limit: $ \lim_{n \to \infty} \prod_{r=3}^n \frac{r^3 - 8}{r^3 + 8} $.