Arctan Evaluation
1. Stating the problem: Evaluate the expression
$$\arctan \left[ \frac{(1+4 \times 3218)^{1/3}}{\sin (\Re (e^{i \pi}))} \right] / \pi$$
2. Calculate the numerator inside the cube root:
$$1 + 4 \times 3218 = 1 + 12872 = 12873$$
3. Compute the cube root:
$$12873^{1/3}$$
This is the cube root of 12873, which we will keep as $12873^{1/3}$ for now.
4. Evaluate the denominator:
First, evaluate $e^{i \pi}$ using Euler's formula:
$$e^{i \pi} = \cos \pi + i \sin \pi = -1 + 0i$$
The real part $\Re(e^{i \pi})$ is:
$$\Re(e^{i \pi}) = -1$$
5. Compute $\sin(\Re(e^{i \pi})) = \sin(-1)$:
Since sine is an odd function:
$$\sin(-1) = -\sin(1)$$
6. Substitute these results back:
$$\arctan \left[ \frac{12873^{1/3}}{-\sin(1)} \right] / \pi = \arctan \left[ -\frac{12873^{1/3}}{\sin(1)} \right] / \pi$$
7. Estimate numerical values:
$$12873^{1/3} \approx 23.0$$
$$\sin(1) \approx 0.84147$$
Thus,
$$-\frac{12873^{1/3}}{\sin(1)} \approx -\frac{23.0}{0.84147} \approx -27.32$$
8. Calculate $\arctan(-27.32)$:
For large negative values, $\arctan(x) \to -\frac{\pi}{2}$,
So,
$$\arctan(-27.32) \approx -\frac{\pi}{2}$$
9. Divide by $\pi$:
$$\frac{-\frac{\pi}{2}}{\pi} = -\frac{1}{2}$$
Final answer:
$$\boxed{-\frac{1}{2}}$$