Complex Equation 162A89
1. The problem is to solve the equation $$\left(z - \frac{1}{\sqrt{2}}\right)^{105} + \left(z + \frac{1}{\sqrt{2}}\right)^{105} = 0$$ where $z \in \mathbb{C}$.
2. This is a complex equation involving powers of binomials. We want to find all complex numbers $z$ satisfying it.
3. Rewrite the equation as:
$$\left(z - \frac{1}{\sqrt{2}}\right)^{105} = -\left(z + \frac{1}{\sqrt{2}}\right)^{105}$$
4. Taking the 105th root on both sides, we get:
$$z - \frac{1}{\sqrt{2}} = \omega \left(z + \frac{1}{\sqrt{2}}\right)$$
where $\omega$ is a 105th root of $-1$.
5. The 105th roots of $-1$ are given by:
$$\omega_k = e^{i\frac{\pi + 2\pi k}{105}}, \quad k=0,1,\ldots,104$$
6. Substitute $\omega = \omega_k$ and solve for $z$:
$$z - \frac{1}{\sqrt{2}} = \omega_k \left(z + \frac{1}{\sqrt{2}}\right)$$
7. Rearranging:
$$z - \omega_k z = \frac{1}{\sqrt{2}} (\omega_k + 1)$$
$$z(1 - \omega_k) = \frac{1}{\sqrt{2}} (\omega_k + 1)$$
8. Provided $1 - \omega_k \neq 0$, solve for $z$:
$$z = \frac{\frac{1}{\sqrt{2}} (\omega_k + 1)}{1 - \omega_k} = \frac{\omega_k + 1}{\sqrt{2}(1 - \omega_k)}$$
9. Note that $1 - \omega_k = 0$ only if $\omega_k = 1$, but $\omega_k$ are 105th roots of $-1$, so $\omega_k \neq 1$.
10. Therefore, the solutions are:
$$\boxed{z_k = \frac{\omega_k + 1}{\sqrt{2}(1 - \omega_k)}, \quad k=0,1,\ldots,104}$$
This gives 105 distinct complex solutions corresponding to the 105th roots of $-1$.
Final answer:
$$z_k = \frac{\omega_k + 1}{\sqrt{2}(1 - \omega_k)}$$ where $$\omega_k = e^{i\frac{\pi + 2\pi k}{105}}, k=0,1,\ldots,104.$$