The graph shown below depicts:
Let's analyze the features of the graph shown:
- The graph has a range from $[0, \frac{\pi}{2}) \cup (\frac{\pi}{2}, \pi]$ and similar behavior mirrored across the X-axis (i.e., also in $[-\pi, -\frac{\pi}{2}) \cup (-\frac{\pi}{2}, 0]$), which corresponds to the principal values of the inverse cosecant function.
- The curve is defined for $|x| \geq 1$ and has vertical asymptotes at $x = -1$ and $x = 1$, which is consistent with $y = \csc^{-1} x$.
- The graph is not periodic, which rules out trigonometric functions like $\csc x$ or $\sec x$, which are periodic.
Therefore, this graph corresponds to the inverse cosecant function: $y = \csc^{-1} x$.

Let \( M \) and \( m \) respectively be the maximum and the minimum values of \( f(x) = \begin{vmatrix} 1 + \sin^2x & \cos^2x & 4\sin4x \\ \sin^2x & 1 + \cos^2x & 4\sin4x \\ \sin^2x & \cos^2x & 1 + 4\sin4x \end{vmatrix}, \quad x \in \mathbb{R} \) for \( x \in \mathbb{R} \). Then \( M^4 - m^4 \) is equal to: