## Trigonometry (11th Edition) Clone

$w^3$ = $- 864 - 864\sqrt{3}i$
$w = 12(cos80^\circ + isin80^\circ) = 12cis80^\circ$ Now, $w^3$ = $(12cis80^\circ)^3$ = $12^3 cis 3\cdot 80^\circ$ (De Moivre’s Theorem) = $1728cis240^\circ$ = $1728(cos240^\circ + isin240^\circ)$ = $1728(-\frac{1}{2} - \frac{\sqrt{3}}{2} i)$ = $- 864 - 864\sqrt{3}i$