Complex Roots 817293
1. **State the problem:** Solve the equation $$z^4 = e^{\frac{2\pi i}{3}}$$ for the complex number $z$.
2. **Formula and rules:** To solve equations of the form $$z^n = w$$ where $w$ is a complex number, we use the formula for the $n$th roots of a complex number:
$$z_k = |w|^{\frac{1}{n}} e^{i \left( \frac{\arg(w) + 2\pi k}{n} \right)}$$
where $k = 0, 1, 2, ..., n-1$.
3. **Identify parameters:** Here, $n=4$ and $$w = e^{\frac{2\pi i}{3}}$$.
The magnitude $|w| = 1$ since it is on the unit circle.
The argument $$\arg(w) = \frac{2\pi}{3}$$.
4. **Calculate the roots:** Using the formula,
$$z_k = 1^{\frac{1}{4}} e^{i \left( \frac{\frac{2\pi}{3} + 2\pi k}{4} \right)} = e^{i \left( \frac{2\pi}{12} + \frac{2\pi k}{4} \right)} = e^{i \left( \frac{\pi}{6} + \frac{\pi k}{2} \right)}$$
for $k=0,1,2,3$.
5. **List all solutions:**
- For $k=0$: $$z_0 = e^{i \frac{\pi}{6}} = \cos\frac{\pi}{6} + i \sin\frac{\pi}{6} = \frac{\sqrt{3}}{2} + \frac{1}{2}i$$
- For $k=1$: $$z_1 = e^{i \left( \frac{\pi}{6} + \frac{\pi}{2} \right)} = e^{i \frac{2\pi}{3}} = -\frac{1}{2} + i \frac{\sqrt{3}}{2}$$
- For $k=2$: $$z_2 = e^{i \left( \frac{\pi}{6} + \pi \right)} = e^{i \frac{7\pi}{6}} = -\frac{\sqrt{3}}{2} - \frac{1}{2}i$$
- For $k=3$: $$z_3 = e^{i \left( \frac{\pi}{6} + \frac{3\pi}{2} \right)} = e^{i \frac{11\pi}{6}} = \frac{\sqrt{3}}{2} - \frac{1}{2}i$$
**Final answer:** The four solutions to $$z^4 = e^{\frac{2\pi i}{3}}$$ are
$$z = \frac{\sqrt{3}}{2} + \frac{1}{2}i, \quad -\frac{1}{2} + \frac{\sqrt{3}}{2}i, \quad -\frac{\sqrt{3}}{2} - \frac{1}{2}i, \quad \frac{\sqrt{3}}{2} - \frac{1}{2}i.$$