Use De Moivre’s Theorem to compute the following:

Question

4 years ago

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Use De Moivre’s Theorem to compute the following:

ula1" title="[3(cos27+isin27)}^5" alt="[3(cos27+isin27)}^5" align="absmiddle" class="latex-formula"> Please explain step by step how it works!

Mathematics

1 answer:

zhannawk [14.2K] · Answer 1 · 2021-12-02T19:29:36+03:00

Hello:
<span>Use De Moivre’s Theorem :
</span>(3(cos27 +isin27)^5 = 3^5( cos(27 × 5) +isin(27 × 5))
= 3^5 ( cos(135)+i sin(135))
= 3^5(-√2/2+i √2/2)
because : cos(135) = -√2/2 and sin(135) = √2/2
(3(cos27 +isin27)^5 = (- 3^5√2/2)+ i ( 3^5√2/2) ...(form : a+ib when
a= (- 3^5√2/2) and b = ( 3^5√2/2)