Fuente TeX:

(e^{\frac{23\pi i}{20}})^{10} = e^{\frac{23\pi i}{2}} = e^{(11\pi + \frac{\pi}{2})i} = \cos(11\pi + \frac{\pi}{2}) + i\sin(11\pi + \frac{\pi}{2}) = \cos(\pi + \frac{\pi}{2}) + i\sin(\pi + \frac{\pi}{2}) = 0 + i(-1) = -i