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[TEX]Z=(1+cos\frac{5\pi}{6}+isin\frac{5\pi}{6})^24[/TEX]
Ta có [TEX]1+cos\frac{5\pi}{6}+isin\frac{5\pi}{6}=2cos^2\frac{5\pi}{12}+2isin\frac{5\pi}{12} cos\frac{5\pi}{12}=2cos\frac{5\pi}{12}[ cos(\frac{5\pi}{12})+isin\frac{5\pi}{12}][/TEX] \Rightarrow [TEX]Z=2^{24}cos10\pi[cos10\pi+isin10\pi]=2^{24}[/TEX]
 
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