Welcome to Westonci.ca, where your questions are met with accurate answers from a community of experts and enthusiasts. Our Q&A platform offers a seamless experience for finding reliable answers from experts in various disciplines. Get precise and detailed answers to your questions from a knowledgeable community of experts on our Q&A platform.

use demoivre's theorem to evaluate the expression (3(cos cos(5pie/6)+isin(5pie/y))))^4 write the answer in rectangular form.

Sagot :

By DeMoivre's theorem,

(3 (cos(5π/6) + i sin(5π/6)))⁴ = 3⁴ (cos(4×5π/6) + i sin(4×5π/6))

… = 81 (cos(20π/6) + i sin(20π/6))

… = 81 (cos(10π/3) + i sin(10π/3))

… = 81 (cos(-2π/3) + i sin(-2π/3))

… = 81 (cos(2π/3) - i sin(2π/3))

… = 81 (-1/2 + √3/2 i )

… = -81/2 + 81√3/2 i