Derivative Tangent
1. We are given two functions: $f(x) = \tan(x)$ and $g(x) = \frac{\pi}{x}$. We need to find the derivative of $f$ evaluated at $g(4)$, which is $f'(g(4))$.
2. First, evaluate $g(4)$:
$$g(4) = \frac{\pi}{4}.$$
3. Next, find $f'(x)$, the derivative of $f(x) = \tan(x)$. Recall that:
$$f'(x) = \sec^2(x).$$
4. Substitute $g(4) = \frac{\pi}{4}$ into $f'(x)$:
$$f'(g(4)) = \sec^2\left(\frac{\pi}{4}\right).$$
5. Evaluate $\sec\left(\frac{\pi}{4}\right)$:
Since $\sec(x) = \frac{1}{\cos(x)}$, and $\cos\left(\frac{\pi}{4}\right) = \frac{\sqrt{2}}{2}$,
$$\sec\left(\frac{\pi}{4}\right) = \frac{1}{\frac{\sqrt{2}}{2}} = \sqrt{2}.$$
6. Therefore:
$$f'(g(4)) = \left(\sqrt{2}\right)^2 = 2.$$
7. The final answer is $2$, which corresponds to option (c).